Noob questions - MP beginners guide for dummies

He's right @vella , those human kits may seem boring at first glance, but they have some very well thought out power combos that make them very effective.
The human engineer, adept, and sentinel in particular should be your friends in the early days, since they can put out significant amounts of damage even with crappy gear.

HEng:


HSent and HDept


HVan:


HInf


HSol

Also, he isn't kidding about armour.
It's not a problem in bronze or silver, but in gold and platinum armoured enemies will be trouble unless you have a gun or power that can cut through it.

Vanilla humans?

So many good answers! These have helped me a lot! Although I can't still understand why I have to max commons first and later get the better gear. I read the explanation, but I just don't understand. Maybe it's just my english then But I will do as you say, buy the cheap packs until I'm maxed out.

My advice would be as follows, which has worked very well for me:

- Buy Recruit Packs until you max out all your common (blue) weapons.
- Buy Veteran Packs until you max out all your uncommon (silver) weapons.
- Buy Spectre Packs until you max out all your uncommon (silver) armor-piercing mods for all weapon types.
- Buy Reserve Packs until you've unlocked all character kits.
- Buy Arsenal Packs until you've maxed out all your rare (gold) weapons.
- Mix in Jumbo Equipment Packs as needed to stock up on consumables (Ops Survival Packs, Medi-Gels, Cobra Missiles, Thermal Clip Packs).
Make sure that you've always got as many of those available as you can carry into your next mission, at the very least.

As has already been said, by taking this route you will evade the chance of getting f.e. a common weapon upgrade in a 99k pack which you could've gotten in a 5k pack instead - thus saving you a lot of money in the process.
Most of the other equipment types will get unlocked as well if you do it this way.
You can buy Spectre Packs to finish any remaining silver mods and gear items - after that, any combination of 99k packs will slowly get you on your way to get your ultra-rare weapons.

I heard rumors, that the Avenger is the best weapon in the game. Is it true? Can I place first on platinum with it?

It is true. With the 'pewpewpew' sound, you know it's going to be deadly. 

Have no manifest? Are a scrub? No problem. Try my patented breakfast of championship ProTip;

I pretty sure this is obvious to almost all players here, but you but I think this is usefull knowledge: in N7HQ you can see all your gear, weapons, classes in one glance. There you can see what stuff you have and what is still locked. Also you can see in what level your stuff is or if it's already maxed out.

So go here and find your account. N7HQ

as i said, vanilla kits are strong. you just prooved my point. Tbh i dont even dislike sticky grenades, actually i love toying with em.

Wut? Sticky nades are ridiculously good.

They are pretty good, but they are not Infernos or Arc's or Clusters or Lift nades. They require much more precision and do not come with other effects like priming.