My first tip to finding a deal is learning what is a deal. Watch prices. Pay attention to how much you spend on every single item that you buy. Pretty soon you'll notice that prices fluctuate and you'll see highs and lows. By buying ahead when the price is low, you don't have to buy it when the price is high.
If you need help remembering prices, you can keep a notebook. This is also a good way to keep track of the different prices of items at different stores.