You're right about line of sight. It is the most important thing to try for. But to get line of sight you need height. Next if you are in the fringe area of the tv transmitter you need a high gain antenna (91XG) with a rotor. Keep the leadin (RG6) as short as possible, use a preamp and keep the number of spliters to a minimum. Using these rules I am able to receive digital transmissions from Toronto, Buffalo, Hamilton and Erie (and a few in between) from my location in Brantford. About 30 total including the sub channels.
50 ' tower with VHF & UHF antenna at the house 45 ' tower with a 91XG yagi with a channel master preamp at the workshop/garage and a Samsung digital receiver.
