If using your site requires specific domain knowledge (e.g., a currency exchange site for money management professionals), then you need to recruit people with that domain knowledge for at least one round of tests. But don’t do it for every round if it will reduce the number of tests you do.

What’s the most important thing to make sure that a Web site is easy to use? The answer is simple. It’s... Don’t make me think! It is the first law of usability.

A Web page should be self-evident, obvious, and self-explanatory. Users are able to “get it” without expending any effort thinking about it.

When you’re creating a site, your job is to get rid of the question marks. Users look at a page that doesn’t make them think, thus there are the thought balloons over their head with positive signs. When they’re looking at a page that makes them think, all the thought balloons have question marks in them.

Needless source of question marks over people’s heads is links and buttons that aren’t obviously clickable. Users should never have to devote a millisecond of thought to whether things are clickable—or not.

People don’t like to puzzle over how to do things. If the people who built the site don’t care enough to make things obvious and easy, it can erode the confidence in the site and its publishers.

Visitors to a site shouldn’t spend their time thinking about, like: Where am I? Where should I begin? Where did they put _____? What are the most important things on this page? Why did they call it that?

Your goal should be for each page to be self-evident, so that just by looking at it the average user3 will know what it is and how to use it.

If you’re doing something original or ground-breaking or something very complicated, you have to settle for self-explanatory where it takes a little thought to “get it”—but only a little.

If you can’t make a page self-evident, you at least need to make it self-explanatory.

On the Internet, the competition is always just one click away, so if you frustrate users they’ll head somewhere else.

Some people will tough it out at sites that frustrate them. Many people who encounter problems with a site tend to blame themselves and not the site.

Making pages self-evident is like having good lighting in a store: it just makes everything seem better. Using a site that doesn’t make us think about unimportant things feels effortless, whereas puzzling over things that don’t matter to us tends to sap our energy and enthusiasm—and time.

Why are things always in the last place you look for them? Because you stop looking when you find them.

There is a big difference between how we think people use Web sites and how they actually use them.

We create sites as people are going to pore and investigate over each page, while (if we’re lucky) they only glance at each new page, scan some of the text, and click on the first link that catches their interest or vaguely resembles the thing they’re looking for.

If you want to design effective Web pages, remember users don’t read pages, they scan them because they’re usually in a hurry; they know they don’t need to read everything; they’ve been scanning newspapers, magazines, and books all their lives to find the parts they’re interested in, and they know that it works.

If you want to design effective Web pages, remember users don’t make optimal choices, they satisfice. As soon as they find a link that seems like it might lead to what they’re looking for, there’s a very good chance that they’ll click it.

Optimizing is hard, and it takes a long time. Satisficing is more efficient.

On poorly designed sites, putting effort into making the best choice doesn’t really help.

There are still users who weigh options before they click. It depends on things like their frame of mind, how pressed they are for time, and how much confidence they have in the site.

If you want to design effective Web pages, remember users don’t figure out how things work. They muddle through.

Faced with any sort of technology, very few people take the time to read instructions. Instead, we forge ahead and muddle through, making up our own vaguely plausible stories about what we’re doing and why it works.

It’s not important. For most of us, it doesn’t matter whether we understand how things work, as long as we can use them. It’s not for lack of intelligence, but for lack of caring.

Once we find something that works - no matter how badly - we tend not to look for a better way. We’ll use a better way if we stumble across one, but we seldom look for one.

If people manage to muddle through so much, does it really matter whether they “get it”? The answer is that it matters a great deal because while muddling through may work sometimes, it tends to be inefficient and error-prone.

If users “get it”, there’s a much better chance that they’ll find what they’re looking for, which is good for them and for you.

If users “get it”, there’s a much better chance that they’ll understand the full range of what your site has to offer—not just the parts that they stumble across.

If users “get it”, there’s a much better chance of steering them to the parts of your site that you want them to see.

If users “get it”, they’ll feel smarter and more in control when they’re using your site, which will bring them back. You can get away with a site that people muddle through only until someone builds one down the street that makes them feel smart.

If your audience is going to act like you’re designing billboards, then design great billboards.

Follow these to make sure they see and understand as much of your site as possible: create a clear visual hierarchy on each page; take advantage of conventions; break pages up into clearly defined areas; make it obvious what’s clickable; minimize noise.

One of the best ways to make a page easy to grasp in a hurry is to make sure that the appearance of the things on the page—all of the visual cues—clearly and accurately portray the relationships between the things on the page.

The more important something is, the more prominent it is. The most important headings are either larger, bolder, in a distinctive color, set off by more white space, or nearer the top of the page—or some combination of the above.

Things that are related logically are also related visually. You can show that things are similar by grouping them together under a heading, displaying them in a similar visual style, or putting them all in a clearly defined area.

Things are “nested” visually to show what’s part of what.

There’s nothing new about visual hierarchies. Every newspaper page uses prominence, grouping, and nesting to give us useful information about the contents of the page before we read a word.

A good visual hierarchy saves us work by pre-processing the page for us, organizing and prioritizing its contents in a way that we can grasp almost instantly.

At some point in our youth, without ever being taught, we all learned to read a newspaper. Not the words, but the conventions. When we know the various conventions of page layout and formatting, it is easier and faster to scan a newspaper and find the stories we are interested in.

Use Web conventions, they’re very useful. Conventions only become conventions if they work. Well applied conventions make it easier for users to go from site to site without expending a lot of effort figuring out how things work.

When you use conventions, don’t follow a great temptation to reinvent it. Sometimes time spent reinventing the wheel results in a revolutionary new rolling device. But sometimes it just amounts of time spent reinventing the wheel.

Innovate when you know you have a better idea and everyone you show it to says “Wow!”, but take advantage of conventions when you don’t.

Break up pages into clearly defined areas; it allows users to decide quickly which areas of the page to focus on and which areas they can safely ignore. Users decide very quickly which parts of the page have useful information and then almost never look at the other parts—almost as though they weren’t there.

The largest part people do on the Web is to look for the next thing to click, it’s important to make it obvious what’s clickable and what’s not. When you force users to think about something that should be mindless, you’re squandering the limited reservoir of patience and goodwill that each user brings to a new site.

One of the great enemies of easy-to-grasp pages is visual noise.

First noise is busy-ness. When everything on the page is clamoring for user’s attention the effect can be overwhelming: Lots of invitations to buy! Lots of exclamation points and bright colors! A lot of shouting going on!

Second noise is background noise. Some pages are like being at a cocktail party; no one source of noise is loud enough to be distracting by itself, but there are a lot of tiny bits of visual noise that wear us down.

Users have varying tolerances for complexity and distractions; some people have no problem with busy pages and background noise, but many do. When you’re designing Web pages, it’s probably a good idea to assume that everything is visual noise until proven otherwise.

It doesn’t matter how many times I have to click, as long as each click is a mindless, unambiguous choice.