I don't know your expertise with HTML, so please forgive me if I sound patronising, or if I go to fast for you.
The first thing an indexing spider will look at is the meta tags. These contain information, such as keywords, and the author's name. These can be very useful, however, DON'T spam them, by filling them with loads of keywords, as many search engines will then mark your site as not be indexed.
These go in the header section of your html page. Here is a sample for the answerbank:
<meta name="keywords" content="Answers, Questions, Answerbank, Who, What, When, Where, Why">
Use a few brief, descriptive keywords here. These will aid in people finding your site with single word searches.
<meta name="description" content="A very useful site where you may post a question and receive an answer from a wide number of users within a very short period of time"> Keep your descriptive short and sweet. It will often get cut off by search engines if it's too long.
<meta name="author" content="Joe Bloggs"> And finally, if anyone wants to find your site by your name.
That's a start, they will aid the indexing spiders. However, these are not all, most search engines will also have a look at the text in the rest of your page and rank you depending on the number of high ranked sites that you link to, and vice versa. Spamming engines are bad, and will often get you banned.
Then of course, you can try submitting your site a) to individual search engines and b) to the www.dmoz.org which is a human edited directory, used by many search engines. Hope this helped.