-Weapon choice is critical. Have a weapon that works effectively at short range(like the Shotgun), and one that works effectively at long range(like the Rocket Launcher or Sniper Rifle or Assault Rifle). If you are especially effective with one gun, use it. As long as you're comfortable with a gun, use it, as you'll get used to it and be better and more effective with it.

 

-Take Cover. If you're fighting a losing battle, hide. Run into an alcove or smaller room and let your shields recharge or get some items if you find any nearby. There is no shame in hiding; you can't always win. Hide, then attack. Also, use the "pop-up" technique. If you're ducking and using a wall or low platform as cover, you can pop up, shooting at enemies, then duck down before they notice or can fight back. This is useful as you won't take much damage and can damage your enemies(note against Elites this will not work, as their shields will recharge quickly).

 

-Use the melee attack. It may not seem powerful, but one hit in the back on any enemy will kill it immediately. You can use it to stun them too. If you find a sleeping Grunt, melee it for an instant kill. Use the melee attack a lot. It is more effective than one may think, and is surprisingly satisfying.

 

-Be methodical. If you run across a bridge full of enemies, guns blazing, you will be surrounded immediately and will take damage. Take it slow. Snipe some enemies, then move slowly, taking one enemy at a time. However, in some cases, charging in a room with guns blazing can work. If you want to clear a room of a few enemies quickly, this works. Or, if you're trying to escape, running in guns blazing, and then leaving the room can be effective. Try to be a good judge on when to run in guns blazing and when not to.

 

-Be greedy. If you find a pile of items, don't be afraid to run in, hoarding everything you can pick up. You don't need to share any of it, just grab it all and come back for some later. However, think before you pick some items. If you only have a few bars of health down and you can see enemies in the next area, don't pick up that medipack. Attack them then come back for the medipack.

 

-Retreat. This ties in with taking cover. If you're being overwhelmed, retreat by backpedaling and firing, then run into another room or corner to reload and charge up your shield.

 

-Always get Overshields after you fight enemies, as you'll probably lose a lot of it if you grab it before you fight or in a middle of a fight.

 

-Remember Elites' shielding recharges just like yours, which is why they like to take cover behind rocks or walls if you injure them. Try to attack them when they're injured, using a melee attack to stagger them or a Plasma Pistol overcharged shot, then finish them off quickly.

 

-If your enemies drop a lot of Grenades, use the Grenades you have and then get them; count the number of Grenades on the ground, use that amount, and then pick them up; I personally never leave a Grenade on the ground; they're too valuable.

 

-Use the follow-up attack, as I call it-fire a weapon constantly at an enemy, then whack them with a melee attack. A good example of this is when fighting an Elite-fire your Assault Rifle about 2/3rds of the clip and melee the Elite. This usually kills them.

 

-Use and drop. This tactic is especially useful against the Flood. Exchanging weapons is a good idea-drop a weapon for another, then when it's out of ammo, exchange it for your original weapon. I'll be suggesting this a lot in my walkthru(if I ever finish it.^-^ ).

 

-Protect your Marines. They're useful, can wipe out a lot of aliens for you, can be funny, and respect you. Kill all Elites and Stealth Elites before they try to take them on; they never win against Stealth Elites, and Elites are hard for them to kill, especially those with swords. They can kill the Grunts and Jackals pretty easily, and also have accurate grenade throws. Also, don't be greedy when in a Warthog. Let your gunner gun them down, don't kick him out of his spot and man the gun yourself. Also try to ram enemies with the Warthog-remember to powerslide.

 

-Concentrated fire. Concentrate on one enemy at a time; except for Grunts, it's hard to kill an Elite by firing at it then another enemy; the Elite's shield will recharge like yours as well, so kill one Elite as soon as possible, then move on to the cowardly Grunts or Jackals.

 

-When driving the Scorpion Tank-remember a few things: 1. Do not fire at enemies who are right next to the tank. You will either kill yourself or your Marines. Run over these enemies or use the machine gun. 2. The Scorpion is powerful, but you can always retreat. If you are feeling overwhelmed, retreat while firing, refresh yourself, maybe backpedal to a health pack or ammo cache, and charge back in. 3. Remember your turret can swing around in all directions, but if you keep on swinging it, you may get confused. Do not fire your cannon unless you are sure it is lined up with your aiming crosshair. A lot of the time people fire their cannons but it turns out the turret was still swinging, so they fire off to the side and must recharge while groups of enemies pound into you and your Marines. 4. Always fire your machine gun when enemies are around- it isn't very powerful, but can provide extra covering fire and can wipe out Grunts and even Elites, Jackals, and very occasionally Hunters. 5. Save your cannon for the bigger enemies-if you use it on a Grunt and realize there are Banshees flying around, Wraiths strafing, and Hunters running around, you may feel a little too overwhelmed. If you are sure that Grunt is the last enemy, you can fire your cannon at it-it's quite funny, but make sure you've cleared the area.

 

-For more tricks, go to the "Halo Greatest Moments" section.