If you find a legendary then that’s cool, but generally stick to yellow gear with decent stats. While you’re out there getting your rift keystones and blood shards you should be on the lookout for yellow pieces of gear with good stats.
Now that the grind to level 70 is out of the way, you’re going to want to switch the difficulty down to normal and keep grinding out those Act I bounties. After you hit level 70, you’ve completed the pre-early game stage of Diablo 3.
Don’t worry too much about gear at this point, just get that damage up and maybe life on hit or something like that. After you’re done with all 5 bounties, leave the game, start a new one, and do it again. You’re going to want to stick to Act I bounties on hard difficulty for now because those provide the best experience/difficulty ratio (normal doesn’t give any bonus, and expert is only an additional 25% for a big difficulty spike).
If you’ve completed the whole campaign (Act V included) on your account then you should be able to jump into adventure mode right away. After doing some digging and experimentation, I’ve found an incredibly efficient model for starting anew as efficiently as possible. You’re eager to get back into Diablo with the arrival of season 2, but you’re dreading the grind to level 70, then torment, then eventually torment VI.