Stock Sidewinder? Just do a few short distance delivery missions to get the general idea. Slowly move away from the starter system and try and find a better market system. You could also try Bounty Hunting at Nav beacons. At your present level you will only come up against NPC ships of the same level, easy meat!
Don't forget that you can lose your original ship many times and they just give you another one. Any other ships you buy, you can lose unless you have the funds to rebuy.
Ok, I have been concentrating on building rep with the factions, do unlock better missions, I have not been to a nav beacon yet, will do that. Absolutely loving the scale of it.