It will sometimes help to power-up at bit in reverse to get a flow started over your rudder before you release the bow lines
. Once you can see water swirling around with side of the transom, cast off you lines
, leave your power on for a moment more to get the boat moving and then shift to neutral. That will give your rudder enough "bit" to give you a bit more control as you leave the slip and you can give yourself a short shot of power as necessay to keep the yacht moving.
Another trick, particularly if you have to steer into a cross-wind, is to use a snubbing line
from your starboard stern cleat
, around your starboard aft piling and back to your starboard stern cleat
. As you ease out of the slip let one end of the line
run but snub it intermittently to swing/hold your stern to starboard. Once your bow is clear ahead, snub the line hard which will cause your stern to pivot around the piling as you continue powering aft at modest throttle. With this you won't even need your rudder which can be preset for a port turn. Continue powering aft until the yacht is perpendicular to your slip. Then power ahead and as the yacht begins to move, cast the line off and let it run back and around the piling as your power ahead and to port clear into your fairway. The line will trail out behind the yacht as you make headway and can be gathered aboard. The snubbing line does not need to be very large for this exercise and can be made of material that will float to insure it won't get pulled into your prop but so long as you wait until you have headway before you cast off, it won't. This approach is particularly helpful for yachts with rolled headsail in a cross-wind as the windage of the rolled headsail will drive the head off without a bit of help. BTDT.