To be a competent sailor, you need three basic skills: first, you must be able to tell which way the wind’s blowing. This is tricky at first for some people, but soon becomes second nature. And sailboats have gadgets to help you: there’s a wind vane at the top of the mast and ribbons or yarns (“telltales”) tied in the rigging that show wind direction; even skilled sailors refer to these aids constantly.
Second, you must be able to steer accurately. This takes most folks about five minutes to learn, maybe ten for those who can’t walk and chew gum at the same time. But you can’t trim (adjust) your sails properly unless you can steer a straight line.
Third, you must learn to recognize when a sail is properly trimmed. With the boat sailing in a straight line (see above), simply ease the “sheet” (the line that controls the sail) until the leading edge of the sail (the “luff”) starts to flutter slightly in and out. Pull the sheet in just enough for the fluttering to stop, and the sail is trimmed. If you change direction, re-trim the sail; expert sailors fiddle with trim all the time.
And that’s sailing, in a nutshell. Doesn’t sound hard, does it?