Start to race!
I suppose you already are a member of a sailing club. If not, become one. But it is a good idea to check upon the club. Does it have dinghy sailing? Do they have dinghy racing on their schedule? What dinghies do they race? If they have racing, perhaps with many different kinds of dinghies, get one of those and start sailing with the club. In some areas, read UK, they sail towards each other with dinghies using a respit system called Portsmouth YardStick, PYS. This is a good way for racing with different dinghies but for many areas worldwide this isn' common.