In Riverwood there is a side quest where you can help out in a lovers triangle between the bard at the inn, the elf hunter and the merchants sister.
Talk to the elf and agree to take his fake letter, that incriminates the bard, to the merchant sister.

She will now not talk to the bard again and you have befriended the elf.

Talk to the elf again and you will now get the option for him to join you on your adventures.
He is a good companion to have until you get lydia.

Here is the trick that should at least give you 3 more levels for free:
1. Talk to the elf and train archery for all the gold you got!
2. Open a trade window with the elf and take back "your" gold.
3. Repeat.

Amusing but almost sounds like a bug/exploit and I'm finding the game on the easy side so don't have any compulsion to rush levels

im playing a archer on expert mode and man its consumes alot of time but it seems more realistic to me, i did run into a forsworn armor set just wish the helm looked better, i loved the antler/horns on it,not sure but i think it gets me in trouble cause it creates more noise?