Summary: Set mine until the 15/30 level, fold everything else except KK and AA, then play fold or shove when you need chips. When you are low on chips, there are situations you should be shoving any two, and when you are comfortable in chips, there are situations when you should be folding AA. Also, fold equity is king. You should almost never be calling shoves (yes, there are exceptions) but doing a lot of shoving yourself. This is a game where the value of chips to your $$ equity is not even close to linear.
Long winded explanation: I have played about 500+ DoN's at the $1 level, 700+ at the $5 level, and am starting to play the $10 so I have a decent number of these under my belt with a healthy win rate. Everyone says that these games have gotten much tougher but they are still very beatable up until the $10 level at the very least. However, because they last longer now, you do have to make adjustments. Doubling up early is no guarantee to cash even at the $5 level. The major pros to playing these is that they can be mass multi tabled (I am able to profitably 40 table the $1, and 16 table the $5), and variance is low. The major cons are the skills necessary to beat these games is relatively specialized meaning it won't help your
poker game much (except bubble play and satellites).
Early on, you should be playing tight because of the aforementioned importance on chip preservation. Early on, as a general rule of thumb, you need an expectation of needing to win 2 chips for every 1 chip you risk. You need a significant preflop edge to do this, or very good implied
odds. This means set mine or play KK/AA only in the early few rounds. If you gain some experience, the next move would be to start stealing from regs that you are fairly certain will fold (we're talking folding to steal in the range of 85+%).
The 25/50 level is a sort of grey level where you should expand your range to maybe QQ+, AKs, but not by much. At the 50/100 level is where the shove fest starts. A couple general rules of thumb for playing shove/fold (and a couple bonus points):
1. The most important thing to consider is your relative stack size. When you are short in chips and are in the sb or on the button and it's folded to you, if the remaning players have medium stack sizes that you can hurt but not large enough that they don't care, it is a shove ATC situation (assuming they don't have like 60/10 stats). If you have like 3000 chips and another 3000 chip player shoves, this is a FOLD ATC situation (and yes I mean fold AA).
2. The number of active players remaining in the hand is VERY VERY important (kind of like position except discounted for people who have entered the pot). If there is a limper in the hand, this should discourage you from shoving because in general, you don't want to get called. If you are UTG or UTG+1, you should be shoving much tighter unless the blinds are about to cripple you (you should try to avoid situations like this but they are sometimes unavoidable).
3. The tighter the table, the more you should be shoving. It is obvious that if the players behind you are tighter, then you can shove wider because the odds of getting called are smaller. This applies for the whole table because when people are tighter, the games last longer and you need more chips to avoid getting blinded out.
4. Almost never call shoves unless you have to (this is Sklansky's gap concept to the fullest). The name of the game is stealing blinds and fold equity. You need to be at least relatively short in chips, and have a SIGNIFICANT edge on villain's range to call shoves.
5. The co-op play. In the final stages of a SnG, if you are relatively comfortable in chips, it is often profitable to call a shortstack shove and just check down the hand. The reason is that by calling, you reduce the short stackers equity in the pot (even if you are behind villains range), and the elimination of a player is of more value then your chips (again, assuming you are relatively comfortable in chips).