A highly effective strategy for most game modes is to stay close to teammates, playing defensibly and using guerrilla tactics will increase your KDR over time. On the other hand rushing in guns blazing can net you more frags while lowering your kdr.
The two currencies of Combat Arms are GP and NX, both can be used to upgrade your character's equipment. This can have a great impact on your in-game effectiveness, this strategy will maximize your use of these in-game currencies.
First of all, Combat arms is known for having awesome events, so always check the calendar for give-aways and challenges, this is how most high ranking players have come to own most of their equipment.
New Players Beware! DONT BUY STUFF, SAVE UP YOUR GP. When you first make your character you receive a starter package, this will contain many guns and equipment. Also, you will be earning tons of GP while you advance through the early levels. This is not normal, within the first few weeks many players run out of GP and either have to buy NX with real money (not a bad thing) or start a new character. It is important to realize that most of the guns you will get and buy only last for 1 day, 7 days 30 days. Only your m16 assault rifle is Permanent.
My advice is to save up until you reach 50,000 GP. You can do this buy using the starter items for the first week. After that every time you log on just buy the following "1-day" items, I will explain why the 7-day and 30-day items do not pay off in the end.
This should be your purchase list every time you log on:
150GP - ACOG scope for the m16
1400GP - L96A1 Sniper Rifle (SGT rank) put this in your backpack
700GP - If you keep dieing get a heavy vest.
Also, try these options if you get bored:
500GP - try wearing a Light Vest to boost your running speed.
300GP - use mines instead of grenades to really boost your KDR and annoy other players!
100GP - modify your pistol with an S1 silencer.
Here are some 1-day guns that you should try (try one at a time, not all in the same day!)
950GP - try the MINIMI Machine gun to get multi-kills.
800GP - try a LAW or RPG these can be A LOT of fun!
800GP - try the MP5A1 SMG for rushing the enemy base.
800GP - try the M4A1 assault rifle for more power.
600GP - try the R870 Shotgun.
Try to get good with your m16 and the L9 sniper, this is the most versatile set up and will help you the most in-game. Try to save up to at least 50,000gp. When you hit 50,000 reward yourself with a 7-day gun if you want, or keep saving. I always make sure I have 100,000 GP saved up because every-once in a while a gun will go on sale for Permanent duration, normally about 100,000gp. So far I have bought a permanent ACR assault rifle, and permanent L96A1, also I used NX to buy a permanent Machine Gun. So I will very rarely buy a 7-day gun. Sometimes I buy an mp5 for a day. and I also like to buy balanced armor for 1000gp because it looks cool :). Other than that I just but a scope for my ACR when I login. so I spend about 150-1950gp every time I log in, and I play for a few hours at a time. Now I will explain why 7-day items may not be good for you.
4,655GP - when you hit 50,000GP reward yourself with the G36 Assault Rifle for 7-days. This is one of the best ARs in the game.
Suppose an item is 100 GP for 1-day, Combat arms will allow you to buy that item for 7days at 550gp, meaning you save 150gp or about 20%. BUT WAIT. you only really save 150gp if you were to play 7 of those 7 days. if you take one day off, and only play 6 of those 7 days you only save 50gp, and if you don’t play for 2 days you lose 50gp. This is why I don’t go for 7-day or 30-day items.