The way I do it is to watch my tachometer. Keep your foot on the brake while slowly letting out the clutch. Keep watching the tach needle. The instant the needle starts to drop below its idle position take your foot off the brake, step on the gas a little, and let the clutch out the rest of the way. By watching the tach you'll know when the clutch starts to engage, so you don't have to guess about when to step on the gas.