I always find the best time to start holiday shopping is in November, sometimes even as early as October. You will find that many stores begin offering one day sales or Pre-Black Friday sales in the early part of November. I personally recommend shopping for some gifts during the early sales in November. Quite frankly, you can't pay me enough to suffer through Black Friday sales. Yes, you can get great deals, but yes, you could also be trampled over because a group of shoppers desperately need to buy toasters for $3. It is just not worth it to me.
Buying items throughout November is your best bet. Of course, it is easier to track sales when you receive email updates. Also, never forget some of your best places to shop are going to be Walmart, Target, Kmart, and dollar stores. This is especially the case if you need a lot of basics like tape, wrapping paper, ornaments, gift bags, decorations, etc. The dollar store is also one of the best places to get low-priced Christmas cards in bulk. If you are the type that still likes to mail out many cards, I would recommend seeing what the dollar store has to offer. Their cards are often the prettiest you are going to find, and of course they will not be expensive.