Definitely best to try and 'snipe' in the last few seconds in my experience. Although if there is very little interest in the item/no bids, then the seller sometimes just withdraws the listing altogether. In the case of a shop I doubt that would ever happen though.
If you are going to try and bid late, best to do it RIGHT at the last minute. Last SECONDS to be precise. Just don't leave it too late. If you're dead serious about winning something, get a stopwatch or something, and sync it with how much time is left on the auction (saves refreshing the page constantly). And then you can time the bid so you hit the button right in the dying moments. Sneaky, eh! :twisted:
I use my dads ebay/paypal account, and never had any problems so far. You're biggest problem is probably getting an arsehole seller. Like the Jackson I won a while ago for a cheap price, (the guy hadn't put a reserve on), and he refused to sell it to me. Other than that, you should have no problems.
The 0 feedback thing I'm not sure. Get in touch with them beforehand, and try and determine their sincerity if you're unsure. Plenty of good pictures is usually a good sign of a genuine seller (as long as the item their depicting is the genuine article of course). If it's a new, private seller, with one picture taken from a website, and a limited product description, then obviously be wary.
Common sense basically. But everyone has to start somewhere, so 0 feedback doesn't mean "uh oh".
Hope that helps somewhat. :D