Organic Syntheses where to start?

It has been a long time since I did organic chemistry, but the way I was taught was to take your product compound and then break it up into smaller units. When breaking it up look at the functional groups to help you to decide where to split the compound. For example if your final product has an ester link you can split that into an acid chloride and an alcohol. This technique is called retrosynthetic analysis. You should read "Organic Synthesis: The Disconnection Approach", by Warren and Wyatt. It's a really good book on the subject and not ridiculously expensive.