The Motion Pro alignment tool works well for this but I most of the time but now I just line up one side of the chain like a gun sight. Easy and quick.
Put a piece of something like a piece of wood broomstick or the handle of an old screwdriver on top of the lower run of the chain and turn the wheel to pull the wood against the sprocket, between chain and sprocket. This pulls the top run of the chain straight. Peer down the upper run from behind, like sighting a gun, and you’ll easily see even a slight curve down the upper run. This aligns the chain sprocket to sprocket regardless of wheel or frame misalignment and doubles to pull the rear wheel against the chain adjusters taking out all the slack.