1st of all best of luck for your first purchase,
if you are planning to buy car from dealer then go for reputed dealer in your area but still don't trust any one 100% ,
if you like any car in your budget then check it from following departments...
1- 15 call center
2- Excise & Taxation department
3- CIA Head Office
if car is clear all these departments then you can go ahead with the deal but make sure don't buy car on open letter, ask seller to transfer the car on your name, it can be done same day within 2 hours time...
don't forget to take ID card copy of the seller and also complete documents of the car with previous owner(s) ID card copies and payment receipt, ( i prefer transfer money into seller account for more safety & record)
Thank you