I'm having some bad mapper's block.

Been asked a bajillion times on this forum really

Look at other successful maps (try with symmetry) and their center points. Good arena maps (ravine, lumberyard), good 5CP maps (badlands, granary, freight), maybe even good ctf maps (ummmm...). Valve maps aren't the only good maps (eg, cp_freight is a successful competitive custom map).

See what makes those good.

Then try and distinguish how each class will perform in each area. Ie, scouts soldiers and demomen can reach high ground, easy to ambush for pyros and spies, plenty of cover against snipers etc.

It might sound like alot of work but if your map plays well it'll pay off.

ETA: Oh and you should draw them up on paper with pencil, so you can see hypothetical situations in your map.

I had the same problem, try to create a point that gives the gameplay that you would like to play as your favorite class (please don't let it be engineer); I mean if it's Soldier or demo you would like vantage points with a clever med pack for those rocket jumps. If you play heavy a reasonable amount of cover to jump-spin around the corners, with a medium area around the control point to keep your minigun effective and ammo to keep Sasha/Natasha full.

If you play spy, you would want corners to decloak or places to engage your oponets for their blind spot; you would also look for places with few transit to flank your enemies or high perches to pull of those epic mid air backstabs and try to find the best exit after a successful backstab.

If you play Scout you would like lots of places to double/FAN jump, a healthy amount of med packs to keep your HP over 100, like the spy you would look for places with few transit to flank enemies and avoid corridors.

I mentioned those classes because Scout and Spy are the ones who suffer the most from bad CP layout, the heavy is an endangerd class and Soldier and Demo are the scrimer's whores. Any other class will have no problem in finding his favorite part around the CP. When you have that worked out you would need to create a fertile soil for the sentry farms, because believe it or not the offense LOVES to destroy sentries; but keep it reasonable.

When you're done with that try to balance the CP to tune down the advantage you will give to your pet class. Having thought about all that, you can now get a good sense of the scale of the map because after a while you get a good feel of how many hammer units a given class will need to hold his ground.

After deciding how to cater to all the classes gameplay you can now create a theme for the CP; make sure to use lots of customs, random junk, contrived frog placements and don't forget to put crates inside inexpugnable chicken wire cages; the crates love it.

Sometimes it is good to just randomly start adding stuff, then your own imagination takes over and turns it into something.

This doesn't always work - Sometimes you put something random, epic fails and can hinder your morale for that particular map.

works and fails for me about 50/50 lol

I commute to school for 2hrs a day so I get alot of time to just think of ways to get good gameplay in my map.

Spend time on general subject like;
How would my map play better?
How would my map look better?
How could I optimize my map better?

Simple things like that, than when you have time test your ideas.