Well, this is probably the most basic tutorial you will ever see. A lot of maps suffer from a problem that is: the map is way too confuse. Well, I'm one of these guys who prefers to watch and learn and it works, trust me. Lets take a look to ut4_kingdom - simple and genious layout.
The whole map is based on a grid - that's why this map is so awesome and you will never, but NEVER forget where you can go. Your maps should always have a meeting spot for teams, like pillars in ut4_turnpike and bridge in ut4_kingdom. This way your map will be playable in TS & CTF.
With this technique you still can/should make some kind of an alternative route, maps shouldn't be always a simple grid.
Comments, sugestions and critics are apreciated.