How much space do you need, how many will be in the car max, what sort of journeys do you do, do you need automatic, can you consider an electric vehicle. Can you pay any advance payment and if so what is the max you will feel comfortable with. What sort of mileage do you do as diesel cars these days have larger advance payments than petrol.
That should do for starters but there will be someone along soon who will ad to the list. Bear in mind due to the chip shortage most cars will be on a 6 month lead time.