I will never pay for razors, shampoo, conditioner, oral care (toothpaste, toothbrushes, dental floss), body wash, or facial cleanser again now that I have discovered couponing. (No, I do not go to the extremes as they made it look on the show the other day!)
Buy on sale or on clearance for gifts. A couple times a year Target has toys on clearance (75% off) to make room for the next season's toys. Young kids don't know or care that the Spiderman or Barbie is six months old if it is in a new box! I got two Strawberry Shortcake sets on clearance at Target for under $6 (one was originally $14.99 and the other was originally $7.99) and gave them to a girl for her birthday a few months later and she LOVED THEM!!
I get school and office supplies during the back to school sales. I get plenty to last...in fact I still have some from two years ago that I got at CVS for free after Extra Care Bucks when they had sales on scissors, notebook paper, printer paper, pens/pencils, rulers, etc. Which brings me to my next point: shop drugstores! If you get to know their system, you can get tons of stuff free or super cheap!
Rebates are another way to save big. Get loyalty cards everywhere you shop and USE THEM!! Get a Upromise account and add all your cards to that account and save for college - for kids or for you!
Start a price book. Keep track of all things you buy regularly, know how much you use, and know your "buy" price. For example, if you bake a lot, keep track of how much flour or sugar you use each month. Then track the price in the stores you shop to see a pattern. (This can take a year or two to truly see the *best* time to buy.) For baking goods, there are two times when they hit very low prices: the 'baking seasons' around Christmas and Easter. If you know your buy price and it hits at those times, buy enough to last until the next sale. Most sales have cycles anywhere from 6 weeks to 4 months. I will not pay over $1 for a box of cereal, so when I see cereal go under a dollar, I buy then.
I buy clothes at thrift stores, garage sales, swap meets, consignment shops, discount stores, and at the end of the season (a size bigger for next year) when they go on clearance. You can also check Craigslist, freecycle, and eBay.
There should be few 'unexpected' expenses in those you listed, as birthdays come at the same time every year, as does Christmas (or Hanukkah, if that's what you celebrate). Gifts can be purchased at any time of the year. See something your brother would love but his birthday is not until October? Buy it anyway and hold onto it until then! (Just don't misplace it.) Keep a gift closet - or a shelf in a closet - where you have several things you have bought over the year for all ages. That way when your kiddo says there is a birthday party tomorrow, you can go there and choose a suitable gift. If you also keep wrapping paper, gift bags and tissue paper on hand then you are good to go! Buy Christmas cards, gift boxes, bags, tags, and wrap now when they are 50-75% off.
I follow some deal blogs that point out what is on sale at the best prices, and usually only buy what I feel is dirt cheap each week. I also use rebate sites when buying online so I can get back some of what I paid. PLEASE PM ME if you want to know more. I can send you my referral links so you can get bonuses for signing up! (There are several places you can get up to 10% back for shopping through them!)