Learn Close Reaching:
In order to master the control of your sailboat, you will need to learn close reaching. You have to use the mainsheet and mainsail as you get the bow pointed in the right direction. If you want to slow down the sailboat then you need to take it easy on the mainsheet. However, if you need to speed up then take the mainsheet and pull in on it. When you want to stop the sailboat then take the mainsheet and give a little slack as this will get the mainsail to luff.
Remember to practice these different control techniques repeatedly to master them. You will need to understand the mechanics of these mainsheet and mainsail methods to get complete control of the sailboat in close quarters.
Learn how to feather:
An important technique that you will need to learn is feathering the boat. In essence you will use the rudder to help slow the boat down. Moving the rudder from one side to other quickly can dramatically reduce the speed of your sailboat.
Into the wind:
Learn how to move your sailboat right into the wind to help slow down or even stop. It will take some time as it is not easy to control the boat going head on into the wind. Luff the sails so make sure you give some slack.
Understand drift rates:
In order to get further control of your sailboat it is important to understand the drift rate. In order to do this, take a 180 degree turn around an object, make a note of the rudder and the time it takes for the boat to move into the wind.
When you are heading into the wind then you can easily use the mainsail to help you make a complete stop by moving it from side to side.