You can use following info about SEO, if you decide to work on your site by yourself
Do not purchase a new domain unless you have to
Due to Google's aging delay for all new domains, your best bet is to use your existing domain website if at all possible. If you're redesigning or starting from scratch and you have to use a brand-new domain for some reason, you can expect to wait a good 9-12 months before your site will show up in Google for any keyword phrases that are important to you. That is called Google sandbox.
Optimize your site for your target audience, not for the search engines.
The search engines are looking for pages that best fit the keyword phrase someone types into their little search box. If those "someones" are typing in search words that relate to what your site offers, then they are most likely members of your target audience. You need to optimize your site to meet *their* needs. If you don't know who your target audience is, then you need to find out one way or another. Look for studies online that might provide demographic information, and visit other sites, communities, or forums where your target audience might hang out and listen to what they discuss. This information will be crucial to your resulting website design, keyword research, and copywriting.
Research your keyword phrases extensively
To find the optimal phrases to optimize for, use research tools such as Overture, Wordtracker, Google AdWords, and Yahoo Search Marketing data. Compile lists of the most relevant phrases for your site, and choose a few different ones for every page.
Label your internal text links and clickable image alt attributes (alt tags) as clearly and descriptively as possible
Your site visitors and the search engines look at the clickable portion of your links (aka the anchor text) to help them understand what they're going to find once they click through. The cool thing about writing your anchor text and alt attributes to be descriptive is that you can almost always describe the page you're pointing to by using its main keyword phrase.
Make sure your site is link-worthy
ther sites linking to yours is a critical component of a successful search engine optimization campaign, as all of the major search engines place a good deal of emphasis on your site's overall link popularity. You can go out and request hundreds or thousands of links, but if your site stinks, why would anyone want to link to it? On the other hand, if your site is full of wonderful, useful information, other sites will naturally link to it without your even asking. It's fine to trade links; just make sure you are providing your site visitors with only the highest quality of related sites.
Do not buy or link to any of the Link Farms
Google doesn’t like link farms. SO never link to link farms. That is my advice. Remember that Google’s spider can see if you are linking to "bad sites". It sees the truth about link connections and their honesty.Google can penalize your website and the result is bad ranking of your website. Google can also ban your website from its index.
Design and categorize your site architecture and navigation based on your keyword research.
Your research may uncover undiscovered areas of interest or ways of categorizing your products/services that you may wish to add to your site. For instance,if your site sellsclothes. There are numerous ways you could categorize and lay out your site so that people will find theclothes they're looking for. Are people looking forclothes to fit their child's stage of development? (Look for keyword phrases such as "children clothes.") Or are they more likely to be seeking specific brands of clothes? Most likely, your keyword research will show you that people are looking for clothes in many different ways. Your job is to make sure that your site's navigation and design showcases the various ways of searching. Make sure you have links to specific-brand pages as well as specific age ranges, specific types of toys, etc.
Program your site to be crawler-friendly
Incorporate your keyword phrases into each page's unique Title tag
Title tags are critical because they're given a lot of weight with every search engine. Whatever keyword phrases you've written your copy around should also be used in your Title tag. Remember that the information that you place in this tag is what will show up as the clickable link to your site at the search engines. Make sure that it accurately reflects the content of the page it's on, while also using the keyword phrases people might be using at a search engine to find your stuff.
Link Exchange - very important
When assessing link exchanges, select sites with a reasonably high PageRank — say, 4 or higher. The higher PageRank benefits your own PageRank when Google evaluates the backlink.Watch out fot thr ome that could be penalized linking to link farms.
This important optimization factor is a measure of how many keywords exist on the page relative to overall text. If your page contains 500 words, and 50 of them are your keywords, the keyword density is 10 percent. Online tools can quickly measure the density of any page.You want a density neither too high nor too low; most optimization pros think 15 percent is a top limit for an article page. Do not stuff your website with keywords.
Always try to have fresh and interesting content on your website
If your site provide others with valuable informations, people will start to link to your site automatically. That will imporve your ranking in search engines, because search engines will see that your site is frequently updated and attracts a lot of people because of it interesting content.