There are many, many ways to improve a web page or websites SEO, but I don't know them all, so I'll focus on a few.
Using correctly formatted URLs will definitely help with Search Engines finding your site when people are on Google or Yahoo, and any other search engines. One way to make sure you URL is formatted is to have “-” (dashes) not underscores, as an underscore can sometimes cause Google to read the URL as one big word, and possibly ignore your site when a person does a Keyword search,
Avoid using common used or ignored words that search engines just remove from searches; like “it”, “I”, and “the”. These words are known as “stop words” and can cause a specific keyword search to overlook you web page if your keywords are riddled with these “stop words”.
Include a meta tag description in the “head” section of your HTML. Make sure the description is representative of the content on your page and accurately describes what the page is about. This description is still sometimes used when search engines are indexing your page, and will be used when a search is initiated and words in the description match the search.
Heading tags are your friend. We always wanna make the most important information stand out when it comes to clients and viewers visiting our page. But what bout the search engines. Well, Google will use words in your heading tags as partial keywords when people do a search, especially the “h1” tag. Also having your heading tags setup correctly on your page will help “searching” on your own page when people visit, as they can tell the where the main information and each section begins if they are headed with
tags. Don't fully rely on using Meta Keywords. It appears as if lately search engines are starting to ignore a large majority of keywords that are loaded into the keywords tag. Now, that doesn't mean give up meta keywords completely. But what you mostly want in the meta keywords tag is either; phrases about your page or main keywords that are content relative to what you web page is actually about.
Make sure all, I repeat ALL, of your images are tagged with title and alt tags. The title tag is simply there to help give your image a name. But its the alt tag that is really important here. It is the determining factor when it comes to a search engine finding your image when someone does an image search. So, no alt tag means none of your images will be found.
Just as the heading tags are used for finding “keywords” for your site and pages. Your web pages title is also used for keywords and used by search engines when doing a search. One way to help search engines locate your site based on the title is: use site specific keywords within the first few characters of the title, include your company name(or your name) if your not well-known, and if possible make the title informative; as if your site has the answer right away for what your viewer is searching for.
Use as many means as possible to get back links back to your site. These links can be posted on your blog, your Facebook, any other social media, or any other kind of site you think would be viable to helping get traffic to your site. This actually seems to be the main way of getting your page “ranked” within search engines now; by having the most “back links” to your site.
Use a Robots.txt file. This file helps tell search engines that the information included in this file is not to be indexed. This way search engines don't “read” your web page and start to consider repetitive information like from different files as duplicates, i.e. your archived files, tagged posts, or categories.
Have a Sitemap for your site. This way if a search engine is “keeping tabs” on your site through bots or crawlers, they will be “informed” or kept up-to-date with new information that is added to your webpage. This is especially helpful if your site involves a blog, or is a social media site like Facebook; with which new information is added and edited constantly.