If you can start with a hot fire and sufficient kindling, you don't always need to do it as a separate step, but otherwise you can burn crumpled newspaper, use

If you can start with a hot fire and sufficient kindling, you don't always need to do it as a separate step, but otherwise you can burn crumpled newspaper, use a hairdryer or heat gun, or sometimes even a large candle. If the room temp is higher than the outside, sometimes just a fan is enough.