Basically, try some tutorials for noobs(10-15), then learn what they do and If you'll get satisfactoty comments then start mixing up ideas which you learnty from the tuts. Will lead you to a good Graphic Designer in future.
For Renders: You can directly get football renders on google and for cricket renders, there are way too many threads in the Graphics Forum of this site. (eg: Simon's, abishakprabu's, Mukesh, Meet{render legend}, etc)
Hopefully this post post won't go as a time-pass and you'll get to your level best.