My general advice, most of which many of you already know, but I'll offer it up again:
1. Do your research. Know the retail prices - and not just on CI but on other sites too. Use the comparison shopper spreadsheet on CigarCyclopedia.
http://www.cigarcyclopedia.com/webapp/content/view/944/48/ Why would you ever pay more at auction than you'd pay at retail?
2. Another great source of information is at
www.c-h-i-m-p.com, which is a database of CI winning bids and prices. It gives you a good sense of what the going rate on CBid is (often very different than the going rate at retail -- case in point: Gurkhas).
3. Set your max price and autobid. Don't get caught up in the auction emotions. The point is to get a good price on cigars, not to win at any cost. If you win, great. If not, you can always bid another day. Most items reappear at auction regularly.
4. Don't be afraid to bid low on high priced sticks. I've been surprised by how often a bid at the low end of the range of reasonableness will win, usually on higher priced sticks but not always. I've picked up 5pks of decent sticks like Perdomo and JdN for under $10, and I've won 5pks of La Aurora 100 Anos, Funete Don Carlos, and Tat Browns, for instance, at prices well below what a 5pk would cost at retail. Yes, retail price for these cigars is high to begin with, but if you're in that market and you can pay $35 for a 5pk that goes for $50 at the lowest priced retailer, you've saved yourself a lot of money.
5. You can sometimes get deals on 5 packs, but I have found that the better deals are on boxes.
6. Early or late? Both. I usually try to bid early, set my maximum price, and forget it. These are the bids that usually win. But sometimes I'll breeze through at about 7pm at night to see if there are any deals to be had. This last minute sniping often works -- so long as I show restraint and don't get caught up in a bidding war.
7. Quickies. I often get a better deal on quickies, because the window of opportunity is smaller. But check around first: I've seen higher bids on quickie lots than on identical lots that are up for the usual 3 days or whatever.
8. There are other auction sites beside CBid where deals can be had. CigarAuctioneer is the Famous auction site. JR Cigars generally auctions boxes. Thompson has both boxes and smaller packs, but I don't go there.
Good luck.