use a bigger lead is the main answer, try using a stiff hooklink so the fish comes straight into contact with the lead. also try shortening the hooklink (some of mine are just 1 or 2 inches long), this helps to eliminate the hooklink from looping - which gives the fish more room to shake the hook before it hits the lead.
Basically, you want the fish to come into contact with a heavy lead as soon as it picks up the bait. If it doesn't it is possible for the fish to sense the hook and shake it out, if the fish 'hits the lead' it will set the hook and the fish will bolt off.
