The first thing I would like to share is a trick to level up your archery for no coin at all.
1. First thing you have to do is tak to Fendal in Riverwood and give Camillia Valerious the letter.
2. You tell Fendal "Follow me, I need your help.
3. Then you ask him if he can train you in archery (spend as much as you can)
4. After that tell him you need to trade some things with him then recollect your gold.
5. Repeat
The only downfall to this is you can only do this up to level 50 Archery.
You can do the same thing more or less with Aela, she raises archery to 75 (Expert). All you have to do is complete the companions questline then any of the guild members can be followers. Buy training and trade for your gold back, you can do that with Heavy armor and two handed to 90 along with one handed, archery, and block to 75.