General Tips:
It is helpful to bring a friend or family member to assist you with your shopping. Do not attempt this alone, especially if you are new to BF.

Instead of going to the closest store, opt for one in a "nicer" area. Go to a city where the median income is high. This way, you are less likely to run into a large "desperate" crowd at your store. The slight extra you may pay in gas is well worth it, considering you will likely get out of the store faster and have more time to go elsewhere.

Many stores give out vouchers (tickets) for doorbuster items. These are typically given out around 4 to 6am, assuming that the store opens at 7. This does make it possible to go elsewhere, and return later, although it is not guaranteed that your item will remain of you arrive much later. If you do  leave, try to return within an hour of the store's opening. The lines for redeeming vouchers is often very long, so it may be more efficient to have someone redeem the item while you continue shopping. 

Timing:
The timing really comes down to what merchandise you want, and how badly you want it. Generally, for popular doorbusters, (i.e. laptops, plasmas etc.) the best time to go to the store should be an hour or two after finishing dinner (9pm-10pm in the evening) This should guarantee you a item , as there is likely to be only one to five people in line at most, and stores should have sufficient inventory for this number. Always, try to get out as soon as possible to go to other stores.

Stores:
Try asking the manager a few days ahead to see what their general plan is.  Building a good relationship with the manager can be very useful, as they may do you favors in return.

Best Buy and Circuit City are generally more organized, as they have been doing BF deals for much longer.

CompUSA can quickly turn into a nightmare due to their midnight opening times. Some have reported that managers had to stand guard in front of the hard drive case to fend off deal-crazed shoppers.  Walmarts are sometimes poorly organized and understaffed. Go only if you are prepared to do battle.

Things to bring:
-Lawn Chairs
-Sleeping Bag
-Flashlight
-DVD player / Laptop
-Food & Drink
-a Friend ( So you can go for bathroom breaks, etc)
-Walkie Talkies or cell phones

Etiquette:

Try your best to get deals, but DO NOT use undue force. Stay calm and focus on your goals. DO NOT push or shove the person in front of you. If you feel like you are being man-handled, simply, chide your offender in a condescending and LOUD tone. This can be avoided by creating close ties with the first twenty or so people in line who have been there since midnight. Do not panic, stay close to your buddy and try to secure your merchandise.

Have Fun!