Too many websites ignore accessibility. But the ability to let people with visual or other constraints (like people using iPhones who can’t see Flash) certainly notice when they can’t use a website. The upshot: they never return.

Here are three sites you can use to help make it easier for people to use your site:

Colour Contrast Check
“The Colour Contrast Check Tool allows to specify a foreground and a background colour and determine if they provide enough of a contrast “when viewed by someone having color deficits or when viewed on a black and white screen”

WAVE
“Rather than providing a complex technical report, WAVE shows the original web page with embedded icons and indicators that reveal the accessibility of that page.”

Browsershots
Browsershots makes screenshots of your web design in different browsers.

Considering that about half the people on the Internet find you through some kind of search engine query, it’s vitally important that you show up everywhere you should. Such are the intricacies of search engine optimization.

Improving your SEO is an on-going task, but here are five mistakes you can make to really kill your SEO strategy.

1. Use images for headings

Some people think regular old text is too boring for headings, so they use pictures instead. A major no-no. Search engines like header tags (< h1 >, < h2 >, etc.), so use these instead of graphics. You can always change the style of them through CSS if you don’t like the way they appear.

2. Leave image tags blank

This mistake is incredibly common, but it’s also incredibly easy to fix. Whenever you have an image display on a page, make sure you fill in the so-called “alt tag.” It’s a handy place to stash keywords (search engines figure anything you illustrate is important, so they pay attention), and it helps with overall accessibility.

3. Bad spelling

Search engines are skeptical of crummy spelling. Get a dictionary.

4. Flash only

Flash is, well, flashy, but it’s not incredibly usable. It’s hard for people to navigate, and also hard for search engines to catalog. Provide an HTML alternative so make everybody happy. As an added bonus, anybody using a hand-held device (like an iPhone) will have an easier time reading your site.

5. Ugly URLs

URLs with a string of nonsensical text does nothing for your site. They’re confusing, you can never type them into an address bar and search engines hate them. Instead, make sure you’re using real English in the address. Check out this article’s address for an example.

Most organizations will spend most of their time designing and maintaining their website’s homepage. And that’s fine. You don’t want to neglect what’s there – the majority of your website’s visitors will see this page before any other.

But thanks to the social media functionality that makes it easy to share individual pages, such as to an event you’re putting on or the bio of someone on your site, it’s increasingly likely that a visitor might use Delicious, Digg, StumbleUpon or Facebook to sneak in around the homepage.

Make sure you think of every page as a potential entry point for website visitors. This means that you may have to adapt internal pages so they make sense to a visitor. From every page, make sure a visitor

• Can access your menus
• Can easily contact you
• Knows they’re on your site – make every page harmonious with every other one

As a test, choose any page at random, and see if you can flow through your site without thinking too hard. Did you know what to do next? If not, jot down what confused you, and make sure you fix it.

It’s a good probability that at least one in 20 people can’t see everything on your website. That’s because a higher number of people than you probably expected are color blind in some way. Some statistics I’ve seen say that as many as 18 percent of people have some kind of visual limitation.

Around 90 percent of the people I tell this fact to are shocked – the rest know it because they’re used to not seeing everything on a website. But what if they’re missing something terribly important, like a news alert or a call for contributions or all your website navigation?

I love the Colorblind Web Page Filter because it makes it easy to see what your website might look like through a color-deficient eyes, those that can’t see red/green or blue/yellow.

For some help choosing the right high-contrast colors for your site, try the Color Laboratory. It’s handy because it “allows you to select colors and see how they appear next to one another, and in various foreground/background combinations. It also allows you to see those colors as they might appear to color-blind users.”

Makes the incredibly important job of picking the right colors easier.