Simple answer, yes. Draughts are the number one cause of people turning the thermostat setting up when that don't really need to, and eliminating draughts can have a big improvement on your thermal comfort. The main places to focus on are window and door frames, P-profile draught excluder is available from any hardware store and is very quick to install.
Remember though, while draughts make you cold, they do provide vital ventilation that can stop condensation forming so if you do seal your house up remember to put a few windows on vent for an hour or so every day, or you'll soon find yourself with mould and damp problems - which is far worse.
The Radfan is the UK's most popular radiator fan and with over 4 stars on Amazon is the most effective way to feel warmer at home.