Originally Posted by king.
That's a big no no. Always shoot in raw. Jpeg compresses the hell out of the files and you don't have the flexibility in post as you do with a raw file.
As far as glass goes, I can't stress enough about getting out of the kit lens series ie 18-55, 55-250, etc. If you don't feel like shelling out for pro L glass, sigma and tokina are still viable options that will produce good results.
18-55mm is a fantastic lens. At least for Nikon it is. Super sharp.