Okay coniferous or deciduous to start with? And, where are you on the planet? It does make a difference!

Remember that those are the ones that keep on growing- and growing - and growing. If you are after a quick screen fast growing trees may not be your best option for more than two or three years and then you'll have a shade problem and possibly neighbour complaints.

Many of the fastest growing trees also have brittle wood, and a tendency for large branches to break--there is a reason why they are called "widow makers"! :/

If you can explain what the problem is maybe we can suggest something suitable? A photo of the situation would help too.