As you can see from my above video that even with such little amount of players its still possible to get a high score. You will realize that when there are such little players on the game most lower-level players are on high alert, mainly leading to camping. A SR71 is always a handy addition to have when its like this (also on free-for-all). Unless you and your team have specific strategies i strongly suggest splitting up from the crowd on team deathmatch. As in the above video you will see that when your team are all bunched up in a area of the map its likely the enemy are in other areas, plus it will always re-spawn them in a less hostile part of the map after they die. Its always nice learning the spawn sites to have the "surprise" element. When browsing through the map always keep to the outter perimeter, here you will know that at least you've always got one angle covered from flanking and being surrounded.

I compiled these tips from personal experience. Im nearly 3rd prestige, never get below 20 kills (on any game format) and i dont camp, glitch or snipe. I stick to assault rifles with red-dot scopes or suppressors (subject to game format).

Galil / G11 + Frag/Semtex - Flashbang - Claymore
Ghost - Steady Aim - Ninja

(Personally i dont concentrate much on getting to the PRO versions of the perks as 50 levels isnt enough to really enjoy them for long before losing them in the prestige mode)