Maximim length about 200 characters. Here should be your keywords, relevant for this actual page, separated by commas, the most important on the beginning. Visit the sites of the SEs and read their instruction. Example Alta Vista . Visit Forums discussing SEs matters.
Many SEs ignore submissions, which they recognize as made automatically by software.
Tip 8 - check and resubmit Check your results and resubmit frequently, especially if you made changes in you pages. Some allow to submit up to 25 pages, some 5 and some only the home page. In any case not more often than once a week, rather once a month. Exeption if you made some significant changes. You might be caught and put on the black list.