There are a number of good guides to help you create a new character.
Character Builder:
I haven't personally used this one, but it seems to be updated a lot: http://sto-builder.binarybit.ch/
Trait Builds:
A very old guide that does a great job of explaining traits and describing how to pick them, even if the traits themselves have been updated since this was written, the general ideas in it are still useful
http://massively.joystiq.com/2010/01/19/massivelys-guide-to-the-character-traits-of-star-trek-online/
STOwiki page for trait builds. Says it may be out of date, so do your research before you committ:
http://www.stowiki.org/Guide:_Suggested_trait_builds
Skill Planners:
With the recent changes, most of the skill planners out there are obsolete and haven't kept up. This one is a different story and is current and up to date:
http://www.stoacademy.com/tools/skillplanner/