1. Try to use static urls over your site rather than dynamic and script driven that keeps changing over a period time, reason is simple when have dynamic url in your website, the url that will be indexed by the search engines may differ from the present url that your actual page might hold. That way you cannot effectively build links back to your site and also there is chance that search bots may find that your url is keep changing and they might well in fact not index your url at all.
2. You need to make sure that you are keeping your url precise and gives you an idea what information that the url may hold. Don’t use keywords in the url for a page that don’t really relate to the keywords used in the url. This way there is chance that your site bounce rate may go up in future and may lead to low ranking pages.
3. Also you need to use keywords, but as mentioned before use your keywords rightly instead of spamming them on your url, when you use right keywords then they have a little influence over your rankings.
4. Use hypens in the url to separate the terms rather than any other separators or no separators at all, next best to hypens is underscore.
5. Try to keep your url structure as simple as possible, you can avoid the usage of words like “of, and, if etc.. in your urls and make it look more cleaner for search engines and also users.