-Carving is ok only in a perfect situation, it's a part of hammer and can be a valuable tool, learn how to use it properly.
-Be patient, rushing through a map will only hurt the quality.
-Practice vertex manipulation on same sized triangle placed together, you can do some neat effects like this when it comes to terrain.
-Make sure when clipping a corner to have your clip start and end points on actual map grid on the lines you are clipping, it could save you grief down the road.
-If something looks stupid, change it.
-Read the forums, look for answers, and if you can't find the answer ask here because this is one of the most helpful and friendly modding communities out there. Thanks for all the help guys!