One of the biggest problems for bowlers at the club net session is that a batsman is down the other end. You bowl the perfect inswinger yet the batsman gets an inside edge and it squirts down to fine leg, at which point he claims it was a legitimate leg glance for four and you get angry. The next one thumps into his pads and you claim an LBW which he claims was missing leg stump by miles.
The fact is, the batsman is a distraction to what you are trying to achieve (and ideally you need will need some practice time without a batsman there). Find the correct line for the ball you're trying to bowl as your stock delivery and practice it. Ignore what shot the batsman plays, imagine the outcome if he wasn't there. For example, an inswing bowler is targeting the stumps for LBWs and Bowleds, so the line must start outside off stump and be full to allow it to swing in. How far depends on the amount of swing you get and any movement you might get off the pitch. Don't get drawn into targeting the batsman as the ball will end up down the leg side.
Once you've sorted out your stock delivery, work on your option balls - variations. That is anything that is different to your stock ball. Perhaps one that just doesn't swing. An effort ball that goes through quicker, a yorker, one that swings the other way, or a slower ball. Then try these out in the nets and don't worry what the distracting batsman down the other end is trying to do.