Well, heaven knows I'm not as frugal as I should be, but I do some things...
-I never buy books. I borrow 'em or use the library. Well, OK, I do buy books, but only from the Red Cross annual book fair, where they're $2 each. And I haven't even done that for a few years, 'cause I ran out of bookshelf space!
-I try to buy clothes from op shops or make them myself (partly for ethical reasons, partly for financial). Clothes come up a lot on Freecycle. I also have a network of friends with small children, and we swap baby clothes and stuff. When I sew clothes, I try to get fabric from op shops too. I don't seem to have the knack of finding vintage patterned sheets in pristine condition like some lucky ladies, but one op shop in my town has a few big fabric bins with pretty good stuff - big pieces, not just scraps. I have about 3 metres of red knit fabric I'm about to make a nursing dress out of, and I got it for about $3. I do occasionally splurge on gorgeous quilting cottons, but if I'm using them to make dresses for DD I'll use them for trims and borders, combined with cheaper fabric like solid-coloured homespun. It looks just as good!
-I make my own laundry powder, which I think saves me money... I never priced it out.
-We go through tons of milk and cream, and it's significantly cheaper at our fruit and veggie store than at the supermarket. Oddly enough, fruit and veggies are usually cheaper at the supermarket.
-I meal plan and then shop. I might change this, though. I usually do a supplementary shop during the week anyway; so what I should do is shop for meat and buy whatever's on special, and then construct the feeding plan (er, that's what we call it) based around that, and then get the rest of the stuff required for those meals. Wouldn't have to be just meat, come to think of it; I often bypass veggies and stuff on special because they're not needed for the meals on the feeding plan.
-I don't shop for fun. I've gotten used to not looking in clothes shops or cookware shops just for the sake of it. Can't be tempted if you don't know it exists, right? (And if you don't see the big "Sale" signs!)