If you are using your basement as your living space you would surely want it stay warm so that your guests never feel unwelcome in your home. This is especially needed if you are staying in colder zones. The best way to keep your basement warm is through wall insulation and ceiling insulation.
Wall insulation can be internal and external. The interior wall insulation would keep cold wave out & hot air in, keeping the space warm all through enhancing all round thermal performance for the basement. The exterior wall insulation process is a more complex but efficient process creating a protection guard for the basement. However, exterior insulation is best done during construction.
Insulating the basement ceiling would also help in creating a warmer ambience inside. But before you go for ceiling insulation, make sure to seal up all the gaps and cracks as otherwise you won’t be able to resist cold air from getting ion into the room.