Don't try to tell your driver what route to take, especially if you're a stranger to his city. He's the expert, and there's no need to antagonize him. If you feel you've been cheated or the driver is incompetent, take it up with a regulatory agency.
It's customary to tip a taxi driver an amount equal to 15-20 percent of the total fare, minus any tolls or other expenses you may have incurred. If the driver's willing to get out of the taxi and help you with your bags, then the tip should be somewhat larger.