I'd give serious consideration to a circular polariser filter if I were you. It allows you to gve some added saturation to sky shots, and reduce the glare and reflection off water and metallic objects (such as cars).
Might be worth reading up a bit on the 'rule of thirds' via google...one of the big differences between ok shots and great shots is the composition. Very few great shots have the subject slapped central in the frame.
Have a nose round here ...it might give you a few ideas and inspiration and you can always question me about techniques I've used.