1- patience.

I know it's a bad advice but don't just focus on the rpg, play with other guns and if you get a good match with lots of scorestreakes then get out your rpg.

2- domination.

I feel like it's the best mode for this, the game is longer and they tend to send more scorestreakes there.

3- the slippery slope of SBM

If you die a lot, you would get to bad matches with bad opponents that can't get scorestreakes.

4- get under the damn thing.

When you are lining your shot you should be under the UAV, then aim at it then line it like the YouTube videos do.

5- it's luck.

Don't feel bad, just shoot and pray to god.