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.
Radfans that live on top of your radiator redirecting heat into your room - perfect for most radiators.
Radfan Slim fits to the bottom of your radiators to accelerate the warm air flow up and around your room. Use with radiators where the Radfan Classic won't fit.