You could try a scumble glaze, to create a 'cracked' paint finish (details of how to use are supplied with the glaze). Alternatively, consider using a light top coat over a darker base, then wire wool on the edges, to give a worn feel. May be best to experiment on spare wood first!!!
I saw a project in a magazine where they painted over the cupboards and then sanded away some of the fresh paint after about 20 minutes using a kitchen scrubbie--not steel wool. Scotchbright scrubbies work well. I tried this and it worked really well but then the magazine said to use a polyurethane over it to keep the finish lasting longer. It doesn't look good with any type of gloss, I found out too late, so if you use the polyurethane get one that has absolutely no gloss. I used a dark green paint as did the project in the magazine. The stores also sell a wood stain in different colors that does a superb job as well, but you would have to strip off any vanish first. It comes in lots of neat antique colors.
You would only sand off the paint in places where it would naturally rub away with years of regular wear and tear--this is what will give it the "antique" look.