"in general", your sails will tell you everything you need to know.
The things to watch for are
-- the gap between the bottom spreader and the jib. 4-6" off the tip of the spreader is probably as much as you want.
-- the telltales on the inside of the genoa luff. If the top ones lift first, the genoa car is too far aft. If the bottom ones break first, the car is too far forward. adjust the car forward or aft until they all lift at about the same time.
-- the leech of the sail. you want it to be smooth, not "hooked"
-- the top batten of the main should be parallel to the boom in light to moderate breeze. If the wind is up, let the main twist off a little too.
-- the telltales on the leech of the main should be streaming, with the top telltale maybe "hiding" behind the sail from time to time.
-- keep any eye on the "slot" - the curve of the back of the jib should be the same shape (top to bottom) as the curve of the back of the main. (choking off the slot - having the jib pulled in too tight - is a sure way to slow down)
There are variations to consider - in more wind, you may want to move the genoa car farther aft than normal to let the top of the jib "twist off" and open up the slot between the jib and the main. You can generally tell it is time to do this when the front third of the main is backwinded.
in breeze, pay attention to the angle of heel. heeling a lot is slow. If you're heeling too much, "feather" (steer a touch closer to the wind), especially in puffs
It's also important to let the boat get up to speed coming out of a tack. Sail the boat a little "fat" (a little below optimal course, just a few degrees) until it has accelerated up to speed. If you grind in the jib right away, it'll take much longer to accelerate.
Beyond that... it's feel. and time spent developing it in a variety of conditions. You'll come to know when the boat feels like it is in the groove...
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