Stud differs from HE in that, while your starting hand stragey is HE is straightforward, it is much more complex in stud. In low limit HORSE I just play really tight. I won't play a 3 str8 or 3 flush for a full bet on 3rd and if I have a split middle pair, I'll tend to toss it unless my kicker is at least as high as the door cards behind me.
In general, if you fold on 4th or 6th your call on 3rd or 5th was wrong.
Live cards, live cards, live cards.
Make sure you have a good idea where you stand on 5th. There are 3 big bet streets in stud as opposed to 2 in flop games. To use a phrase from the movie "Ronin", "Whenever there's any doubt, there is no doubt."
Did I mention live cards?
Kickers? If you have a pair TT+ on 3rd, split or buried, the kicker being a straight flush card to one of the pair cards is a huge plus.
Position? You always have to be aware that position can change street to street, so if you make a play now because you're in position, how does that impact future decisions if you pair your top card or catch a live A and are OOP on the next street?
The Stud section in the original Super/System by Chip Reese is great. Now that I mentioned it, I need to dig out the book and read it again.
I don't play enough Stud High to be comfortable that I'm making optimal decisions a lot of the time. I play a lot of Stud/8 and feel more comfortable with that game.