Tips on buying a car first time!?

hiii everyone I’m currently a 18 year old girl looking to buy her first car in the next year (my birthday is in march and I’ll be 19) I’m hoping to buy my first car when I’m 20. Any tips would be great, unfortunately I don’t have much support at home and would have to buy the car all myself with my own money and everything, I’m looking for a used car that I can pay off right away or have a low car payment. Any advice would be appreciated:) Also where to look as well!