You need immigration clearance of T&T before flying to T&T. There are many routes but as Pakistanis are not allowed to fly on easy routes and they need airport visa. Airport visa is also not possible for many people and time consuming factor. Search the routes where you can stay on the airport without a visa. Buy online tickets and just fly.
If you don,t have credit card then visit to the main office or branch office emirates, qatar and they can link the ticket and buy return tickets otherwise you will face problems in different airports.
Try to speak English and communicate well. Respect yourself and you will be respected, you can visit T&T