Im awful at crucible

Use a play-style that is unique to you. For example, I main the empyrean bellicose, with flashbangs, and a preydyth's timepiece/hand cannon for sweats. Using a playstyle that is unique to yourself will help strengthen that play style's pros and cons. You'll automatically learn to be more accustom to your downfalls, and hence forth, die less. Rumble is the best place to practice. Rumble promotes primary usage. Find a good primary, and use it in every engagement, only use your sniper when to get a nice double, kill a rushing shotgunner, or for long range. Don't use a shotgun. Last tip, find a way to play with the best players in destiny. I've played with nearly all of the top players on my system when I was starting, from then, i've grown into one of them. It's either adapt, or fail, and your brain does not like to fail.

Play rumble it's a primary type game and it helps u in those tough spots in trials and in other game modes I would say find a primary that u like and fits u work on making build when u get armor and what I mean by that is if u get a chest piece that intellect discipline sniper ammo keep it try and find those kinds of armor try the hacksaw the last work doctrine of passing mida ect I would say don't use autos or scouts for the most part

oh, start playing with only your primary weapon and then move on to something like a sniper for trials with is much more efficient for getting kills at a longer range. If you practice with aim acceleration and aim assistance, using a weapon like a sniper will feel almost natural to you

Practice makes perfect that's the way I got really good a crucible

Practice, Knowledge is key know what weapons are good to use(as well as perks with the weapons) and what perks are good to use on your class.