It is very possible to have a successful short sale but not all short sales are created equally, Here are a few things you should ask/and or look at before you take the listing:
1. How much do they owe on the mortgage?
2. Are there multiple mortgages on the home?
3. Have they declared bankruptcy?
4. What do the comparables (CMA)(BPO) say the home is worth?
5. When was the last time they paid the mortgage?
6. Who are the banks that are holding the note?
Knowing this information will give you a good idea of wheather or not you will "weather the storm" and have a successful short sale and CLOSE on the listing.