I would say avoid big games especially Ground War. It seems it's easier to get kills because there's more people but in fact it's a lot harder to get high kill streak because of bigger chance of getting killed.
Do learn the maps as fast as you can so you can easily pick good spots and avoid those from where you can get killed from easily. Watch killcams for that (as was suggested in the answer to another question).
Unlock challenges for the same gun to get optimal performance out of it. Almost every gun (at least from assault rifles) can be configured to be effective.
Lastly, try to play stealth to avoid many deaths and therefore build higher streaks. Use silencer, Ninja and Cold Blooded for that.
Well, before I jump directly into answering this, lets investigate the ways you can gain the most money, which in turn allows you to buy the most stuff.
Contracts
Its partially depends on your ability to fulfill contracts. If you can successfully complete high reward contracts you will gain more money and more experience at a greater rate then players who cannot. Try and make sure you always have an 'active' contract so your kills are constantly working towards something.
Gun Challenges
Its also worth noting that more kills trumps completing challenges almost every time. What I mean by this is don't spend your time on a gun you suck with for experience. The opportunity cost of the kills you didn't get by using a crappy gun greatly outweighs the experience you gain from the challenges. By using a better gun you'll get more kill streaks which in turn gives you more experience and more kill streaks, and kill streaks also give experience!
Kill Streaks
Pick low kill streak rewards (as these provide you with extra experience every time you call them in) and try and get these often (hardline?). Keep in mind that getting dogs, while awesome (11 kill streak) provides THE SAME AMOUNT of experience as calling in a spy plane. By using low achievable kill streaks you will gain more experience by using the kill streak, gain more experience by challenges for the kill streak, and gain more experience by the kills you get when your kill streaks are up! Most of this game is about snowballing your momentum.
Equipment
One of the most often over looked ways of gaining experience. Not utilizing your equipment is bottom line a wasted opportunity. Don't think of throwing that flash bang grenade as -wasted- think of it as utilized. Every time you die with out throwing your flashbang you have wasted the opportunity to potentially save your life, potentially get a kill, and work on your equipment challenges. Wasted equipment is sad equipment. Utilized equipment is just one more lair of the snowball (see above)
Keeping these things in mind will help you level up faster, but its worth reiterating the most important part of this description. If you are using crappy perks and crappy guns to get challenges YOU WILL LOSE EXPERIENCE. The smarter you play (low kill streaks, great perks, great gun) the more kills you'll get which will lead to more kill streaks which will lead to more challenges which will lead to more experience!
Thesis
Now this seemed like a long detour to the point, but here it is. If you play better you can afford to buy more points. There is nothing wrong with "This looks neat" when you have a ton of cash laying around from following my above examples.
As far as an 'optimum route' this really depends on how you play. Ever had a friend argue with you for hours about how 'their xyz' is always the best but it just doesn't work for you? You and I will be significantly better with different guns and different perks, but you wont find whats 'optimized' for you until you try it. Buy as much as you can and try it out on a 'test' class while you get a feel for which guns and perk choices fit your play style best. Want a pink rabbit emblem on your Famas that is strictly asthetic? Go for it. Want to try a new gun? Go for it. Just make sure you always dedicate a class to something you know you can kick ass with. That will give you a fall back while you investigate which perks and guns are good for you!
Hope this helps
Starting Classes that work for me
While purely subjective, here are some classes that might help you get started
My favorite assult rifle class (5 k/d ratio) large maps
- Galil (best assult rifle I have unlocked so far could also be Famas)
- Red dot + Silencer (keeps me off the radar)
- Frag + Concussive grenade + claymore
- Hardline or Ghost (depends on amount of spy planes)
- Warlord (for the 2 attachments)
- Ninja (if you wear a good pair of headphones it will change your life)
My favorite SMG class (4.2 k/d) Small maps (NukeTown etc)
- Ak 74u w/ grip or silencer
- Semtex or frag, concussive, and Motion Sensor
- lightweight or hardline or ghost (depending on map size + spy plane)
- hardened (Bullet penetration, may have botched the name)
- Ninja (as always)
Edit: Found this for another question, thought it would be applicable here as well:
Call of Duty Black Ops Weapon chart with damage, range, rate of fire, recoil, ammo, reload time, and body multipliers to help you choose the right weapon for you =)
Best Answer
Once you've reviewed the game(s) in the theater, click on the "Friends" button in the lower right on the main menu screen (multiplayer main menu). You'll see a tab for recently seen players. Find the player, click on them and click the button to view their player card. On there should be a button to report them.
I'm not near a machine with the game on it, so my instructions above might not be perfect, but hopefully they are close enough to get you there.
Also, keep in mind that some players out there are just sickly good. I've often been convinced that someone was a cheater then in theater realized that they were missing a lot of shots too. Or as a ghost I've been followed through a wall only to see in the theater that they were constantly careful when going around corners (not something that a wall hacker would be concerned with) and just happened to have an SR-whatever in the air when they killed me or saw a small piece of me running behind cover.