My charts for my nearly 3 y.o. twins are very, very simple. Their names are on them. Sometimes they will "write" their own name on the top. I have jumbo books of stickers from Walgreens that are about 500 stickers for $1. I let them pick a sticker from a sheet and put it on the chart.
In talking to friends who have used sticker charts, I think what has made mine really successful is having immediate gratification/rewards when they earned a sticker.
For instance, when my daughter was potty-training, she struggled with pooing in the potty. My sense was that she was a little afraid because she NEVER went in the potty but consistently peed in the potty. I bought oodles of gel pens, little notebooks, cool markers, etc. Each individual pen, marker, etc. was a prize that they earned. When she pooped in the potty, she immediately got to pick a prize as well as put a sticker on the chart. At the same time, I told her that when she received 5 stickers, she would receive the coveted ladybug brush and comb set. I wouldn't let her hold it until she earned it. If she reverted to pooping in her panties, I just calmly told her that was too bad because if she had went on the potty she would have gotten to pick a prize. I got down the prize bag and showed her all the things she might have been able to pick. I also told her she would get lots more opportunities to earn prizes and that she could try again next time.
I quickly phased out awards for potty-training once she consistently went in the potty, which was after 2 days. At that point, I started awarding stickers for picking up toys. I give larger awards and more immediate ones when we are struggling more with it. I try to keep it really concrete. E.g., picking up the legos earns a sticker, picking up the railroad set earns a sticker.