This is something that should be examined closely compared to the previous versions of HALO. There is an exceptional change in close quarter combat in HALO Reach compared to HALO 3. In HALO 3 there is something that was called the bleed through system in which, if you attacked an individual and their shields were extremely low, you could do a melee attack on the other player and the large amount of damage would bleed through the shield protection into the life bar of the other player. This is not the case in HALO Reach. In HALO Reach, if you bring the shields down so there is very little shields left, then you do a melee attack, it will eliminate the remaining amount of shields but it will not bleed through to the health of the other player. As a result the other player continues to stay alive.
This dramatically changes close quarters strategy in that the time to perform a melee attack on an opponent is almost never worth while. It takes time to approach an opponent and it also takes time to hit and recover from hitting your opponent with a melee attack. What this means is during the time you're attempting to perform a melee attack your opponent has the opportunity to shoot at you multiple times and may even dodge the melee attack. As a result the melee attack is not worth the effort in close quarters combat. You will be better served by trying to get a few more rounds of shots off on your opponent and improve your angle and placement. 
There are some times when a melee attack does make sense, but it usually involves getting off the melee attack early in the confrontation. A surprise attack may serve you well when performing a melee attack. Since this is a lower percentage of encounters we recommend that creating the muscle memory of close quarters shooting is much more beneficial to you as a player and will serve you in the long run much better than performing the melee attack.
One of the other big differences is in HALO Reach you can view your physical life bar. In HALO 3, even though you had a physical life bar, it was not visible. In HALO Reach even though you have a physical life bar there are no medics with ACLS online renewal that can perform resuscitation if the life bar goes to zero. Even though there are no medics with ACLS online renewal you can still obtain life or medic packs that will increase your life so they serve a similar purpose. 
The other thing that should be noted is related to the use of the DMR and performing 2 quick shots verses letting the gun return to normal after recoil. Testing shows that performing two quick shots with the DMR does not greatly affect the accuracy of the weapon and so the technique should be used on a regular basis in both close quarters or long distance attacks. We have included a video to help demonstrate better the points that were shared here today. Good luck implementing these techniques and we wish you the best in your HALO Reach hunting.
One of the most important things to know about HALO Reach is when the weapons are going to spawn. This is a very easy and predictable thing related to gameplay and one of the most commonly ignored things by new players. Knowing when power weapons are going to respawn is crucial for dominating any map in the game and also crucial for your success. 
The spawn times for various and important weapons in the game include the shotgun, sniper rifle, rocket launcher, and the sword each take three minutes to spawn. Other secondary power weapons such as the grenade launcher takes one and a half minutes to respawn. The DMR and the needle rifle each take one minute to respawn. We know some of these readers enjoy using those weapons. The needler and also the plasma pistol only take 30 seconds to respawn. This is good to know because these are actually some of the most powerful weapons in the game if they are used correctly. It is also important to note that the frag and plasma grenades take 45 seconds to respawn as well. 
Once you pick up the weapon you will want to hold onto it for at least the normal spawn time or longer. This prevents the weapon from respawning and other users from being able to pick up these power weapons. Even if the weapon is empty of ammunition the weapon will not respawn until it is dropped and discarded. If you do pick up another weapon you will see that the power weapon will immediately respawn if the three minutes has elapsed. This is good to know if you have the power weapon, are close to where the power weapon spawns and are out of ammunition. You can simply drop the weapon and have it respawn next to you if the three minutes has elapsed. Another thing to remember is if an object is dropped or lost because of death it takes a total of 34 seconds for that object to disappear. This is also important to recognize if someone with a power weapon is killed in battle and you are interested in collecting their weapon that was dropped. 
Now that you know the timing related to respawning of power weapons, you can have a better concept of when you should fall back, pick up a power weapon, and regain control of the map and overall kills. Knowing the timing and location of power weapons on every map is basic for success in HALO Reach. Trying to become a competitor in this gaming field is almost impossible without this basic understanding. 
You need to remember that there are no teammates in HALO Reach with ACLS online renewal that can save you after death. This game is not designed around respawning with ACLS online renewal like in other shooter games. After successfully beating the enemy you can gain badges or certifications in the game that allows you to show your status. These certifications are popular among players because many of them are rare. We have included a video that discusses and shows in detail how to implement these HALO Reach tips.