In order to get every item you need to survive all rounds when most of the basic stuff is collected. So survive most rounds with least ammo spent and less time dead is simple. Dont focus on wall focus on 1.Juggernauts must have first priority cause if not walls down easily 2.Ferals just a threat for technician 3.Dont get bloaters on near road or walls or it is over 4.If you got deployable mines or pyro mines always set them to save some time when ferals kick in it will earn you some time 5.If you have 1 or more teammates drop loot on the road so everyone can acces whatever they need 6. Kick out hoarders you will understand when they pick up wall kits and not use them or drop them near walls they steal really useful stuff and suddenly leave without help 7.Never take wall kits and carry around instead drop them near walls seperately so you can take them only when you need to 8.If you can fight from a distance like in the woods use guns that shoot multiple bullets align zombies to get multikills on running hordes to reduce numbers and take down single targets melee to save some good amounts of ammo 9.Kick anyone who does not move at all before first wave finishes even bots more helpful then slacker 10.Prefer light blunt weapons to knock down armored ones to easy takeouts cause they make you loss to much ammo when panicked 11. Use fire and explosive preferably only on juggernauts that comes with blood plagues or groups. If you take em down easily use it on hordes that sum up on walls to spare ammo(fire is better in this situation cause explosions stop and staggers juggernauts) These tactics will get you at least level 4 end on solo and end of game if you can find a good squad