The best thing about Borderlands, and I’m sure few would argue, is the cooperative play. And while playing with friends is similar to playing by yourself, there are a few crucial strategies that you should learn.
You can respec at any New-U station for a fee. This becomes very important in multiplayer as each class has skills that can benefit the team in some way. When playing co-op, always respec yourself to benefit the team. This is very important. The soldier can heal teammates, the berserker can become an effective tank, taking most of the enemy damage, and the Hunter and Siren can increase the XP their team receives. Always take care of the team, and the team will take care of you!
Bandit hideouts usually contain an assortment of enemies, all with different tactics. Snipers will often hang back inside the base and shoot you as you approach. A good way to combat this is to have someone, usually a hunter, stay back and counter-snipe, while the rest of the team can protect the hunter by getting up close and personal with the oncoming enemies.
Exploit the hell out of the second wind system. When you’re taking on a large group of enemies, or you just have reason to believe that you’re going to die a time or two, have one character hide behind cover as the dedicated reviver. Then, have another character stand next to them, outside of cover, and open fire. Each time the attacking player dies, he or she can be revived by the player behind cover. You can repeat this strategy until all the enemies are dead. The best part is that you can still fire while you’re down, so the attacker never needs to let up on the onslaught.
You can use the runner turret to great effect when taking on enemy compounds. Park the runner in front of an enemy compound with someone manning the turret and then have the driver run into the base and lure the enemies back out, so that they can be met with turret fire. To make this strategy even more effective, the driver can hop back into the runner and use the front-mounted machine gun. It only fires in a straight line, but if you positioned the vehicle correctly, it should still help. Obviously, a berserker with a lot of skill points in the tank tree makes the best bait, as he can absorb the most damage.
Article from Gamersyndrome.com