If you live in a pre 1910 Victorian or earlier terraced home most likely you will only have a few problems compared to a lot of others house types
Draughts round windows and doors and window surrounds
Draughty floor boards and skirtings
Draughty doors and loft trap,
Draughty windows or window surrounds
Draughts round waste pipes.
Modern terraced houses will have a lot more problems than the above including:-
Draughty party wall if it is of cavity construction and all the problems of cavity walled homes