Check your supply valves, sometimes the washers stick. Check the aerator.

Sometimes, if you use teflon tape on threads, it can get in the way. You might have to re-do your connections.

One other thing to look at, take off the aerators and flush the faucet and screens. I happen to have old galvanized pipes, and if I shut the water off in the house for any reason the surge of pressure from turning it back on loosens the crap in the pipes and I have to flush those faucets. Soon though I wont have to do that since I am replacing all the lines with a 1" main line and branching off to the individual rooms.