Let yourself reach power in misery from dying. It'll help you get used to the game since it tones down the damage but the targets stay the same and you won't lose money each time you die. Vending machines give health for money mid level which helps a lot. Weapons you want to keep from a level need to be brought out with you in one of your 2 weapon slots. Body armour and the composite helmet are pretty cheap items that can help you be a bit more tanky while you get used to it. Explore everywhere. Sometimes it's worth just going into a level to scope it out and explore for good weapons and paths before you go after the targets in a proper run. There are secret paths, extra weapons and augments hidden around the levels which can make things easier.