Sheriff's Sale clarifying questions

Brand new to REI and just getting through Dean's "Be a Real Estate Millionaire" book. Actually, this is my first post. Recently found Sheriff's Sale from the Foreclosure Alert. Went to see the property (in New Jersey), but unclear on the process regarding Sheriff's Sales. I did search for it in the forum but only found that the "Bank sells the property at an auction". I would have assumed that this was a situation where the County was just looking to reclaim back taxes. So after this lengthy recap, here are my questions:
1) Can I contact the Lender or owner in advance of the Auction and make a deal?
2) Is the auction a situation where I can't actually see the inside of the property in advance?
3) I saw references in my content search that Sheriff's Sales can be really tricky - can anyone w/ experience explain this?
4) For the auction, assuming I get the facts I need in advance, do I just show up w/ a Bank Check for whatever I plan to bid? Do I need anything / anyone else?
5) Note that I have not even been pre-approved yet - is this an obstacle for an auction?
Sorry for the lengthy post, but I sense this could be a great source for getting useful info. Look forward to anyone interested in helping me learn and get my feet on the ground. Thanks.