allright. heres what i suggest. first get a program which you know you want to use. then you can start practicing on pictures but first get yourself aquanted with the program. start off with simple effects and get on to more advanced. try using tutorials such as bluesfear and such. then just have fun with whatever you want to create. it doesnt matter if its abstract or objective. just enjoy yourself.
Ps: it doesnt matter if ppl dont like your work. all that matters is that you like it for what you see in it.
one more thing. sigs arent always small but whenever i make sigs i start out big (700 by 250) and i work big. i can focus on the details better that way. once u think ur done make it smaller ( i usually make it 400 by 143)
great attempt for a first try!!!