No, you don't need doorways. Optimize existing web pages by adding well constructed meta tags, carefully selected keywords, keyword-driven title tag, and theme rich content. Focus pages on one or two themes and optimize for those keywords. A site that goes off into too many different directions is hard to rank. Roughly 4-6 weeks is how long I wait after submitting clients because earlier checkups have proved a waste of my time.
Results are sporadic.
Do NOT submit your site every day, or every week . Engines simply don't reindex this often. Do not submit every page of your site. Once your site is in a database, many engines send their own spiders to your server for retrieval of new pages and to get your updated pages. Only submit pages with content that has been changed.