The skill displayed in people doing cayo with full stealth so fast amazes me

I have been trying to solo cayo lastly , tryingto be stealthy.I am a fan of hitman games but I am terrible at stealth in GTA.I have seen people who do it full stealth very fast and super headhots all guards so fast.Do you have tricks to killl guards so quickly?One thing I struggle with is doing two headhots in a row, like if two guards are talking to each other. I wonder if it is easier todo in first person view , or if I should just totry to use brute force ans in an ordinary gta mission. How do you do cayo do you do full stealth or do you fight in a frontal way?