ok, If your tank is the one in your avatar (I assume it is) then you need to plant the heck out of it first, and then add your shrimp.
1. shrimp like live plants in order to really make them comfortable and thrive
2. if you plant really densely then they will have more hiding spots to hide from your fish (which will otherwise always be after them)
3. the only real threat fish-wise I see in there is the angelfish, and the molly if those are BIG.
With more cover from plants, I think you can get away with around 10 or so cherry shrimp or perhaps 4-5 amano shrimp. those two species I suggest for beginners. Having had cherry shrimp for a while (from 6 I got more than 40 now) I would sorta be biased on those
What's more I've kept my shrimp with predatory fish like Bettas, swordtails and a goldfish. believe me Live plant cover matters!