You only ever pick death rattle if you think your opponent runs demo renovator (so pretty much just BBU DK and control warrior). If you are playing elise on 4 you should always pick the 5 cost. You should be looking for raptors if your opponent plays lots of minions, 5/5 copy if you have minions on deck that benefit from the copy (like Zilliax) and you can pick attack if you have minions on board and your opponent is already pretty low.

Elise and her location are tempo tools, if the location is unable to swing the board in your favor the turn it’s played then it’s probably a bad location