Fatboy
I really think you should do one of two things:
First (and preferred) - pick up a pencil and some paper. Draw out 6 or so designs - ALL DIFFERENT to the last. Improve on each design with elements etc - but be cautious NOT to overdo it. Make it a habit to draw - even in bed for 10 minutes each night before retiring.
Second - look at some of the image galleries on some of the better websites. Look carefully at them and ask "what makes this a good / great sign". Is it the colour composition, the layout, the fonts, the feel, the message, the eye appeal? Really it should be all seven aspects. YES !!! simple signs can look magic with the right curve, or contrast, or drop shadow.
Nobody - including you will improve by trying to improve yourself as opposed to emulating others. Those that do it and do it well are "Gods", and have learnt by experience. Follow them.
Cheers - G