Here's some tips coming from a player with over 500 hours in the game.
If you are farming use Nekros with Desecrate. You will find items more easily. I have found half a dozen Tranquil Cleaves right after the update using my Nekros. I kept one and sold the rest when they were high priced. Plat in the bank.
Also if you intend to solo missions especially defense, Excalibur is your man. A decked out Excalibur can do ODD forever solo. My friend tried it with his Excalibur and managed to hit wave 80 no problem before getting bored and leaving. He actually hasn't touched the game in a couple months because he claims its just way too easy. He likes to be challenged.
One last thing. If you are going to do high level content then you should stack up corrosive damage because enemy armor becomes a ***** once you're in a mission so long. I have a Boltor Prime with 1k corrosive atm (still not done upgrading) and it can shred through level 60 enemies easily.
Have fun out there Tenno.