My M-60 tips. Read and learn.

Do not be scared to take the long distance pop shots. Pop shots from across the map are effective means to get your opponet to turn around and come back to you. You may also be able to snag the kill but you can not do it with the trigger down. Long shots have to be done in burst to keep the recoil down.

Firefights. If you are in a firefight hold the trigger down and rush to your opponet. Dive, prone, stand up, and sway. Keep holding the trigger. You will be able to apply 10X as many rounds while they reload.

Hide. The surprise attack is key with a M60. If someone comes around the corner. You will have already lit them up with 25 rounds.

To my surprise, I get more headshots out of this gun then any other. Maybe it is because I use it all of the time. Always aim for the chest. The recoil provides excellent aim for headshots.

Cover Fire. If you are using this gun, you are a back-up player. You must be able to provide cover fire for the guys with M4A1, 552, M14, etc. When they rush you lay down a blanket of fire. Just be aware of where your teamates are. If friendly fire is off go prone and let it go.

Prone. You have the best accuracy when you go prone. The gun steadies itself and your pattern is tighter.

Ammo supply. You have three clips of 100 rounds. The trick is to hit your reload button before your run out. This keeps you at three clips no matter how many you use. Thus, never running out of ammo. There have been rounds I know I used 700 rounds.

Hit percentage. If you care about hit percentage this is not your gun. Find something else. My hit percentage is usually around 9%.
Hope this helps.
EL