Note: This thread is targeted towards gamers that play the latest titles like battlefield 4.
A. CPU: the central processing unit is the 2nd most important chip in a gaming laptop, this is because games like battlefield 4, watchdogs, assassins creed 4 etc. use a lot more horsepower than previous generations of games to run all the games functions. This is especially true for multiplayer, since your cpu has to keep track of dozens of players which requires a lot of processing to not start lagging (this is mainly for P2P multiplayer).
For intensive games like battlefield and watchdogs, a Intel core i7 quad core processor is a must, a dual core i5 could do it but it would slow the game down. Don't get an AMD APU quad core, as those have weaker cores than intel's stronger quad core processors.
B. Part 1 GPU: the graphics processing unit is the most important chip in a gaming laptop, because it is the one doing all the hard work of giving you all the eye candy (like MSAA, particles, PhysX, etc) you need a powerful gpu to run very demanding games. Unfortunately, very few laptops have AMD Radeon HD graphics in them, so I will be only recommending NVIDIA Geforce GTX gpus.
The minimum requirement for gaming laptops would be the Geforce GTX 850M or GTX 760M. Any of the GeForce GTX 700 and 800 series is good for todays games, however I'd suggest if you can get one of the GeForce GTX 800 series as it has better features like, battery boost, 3d surround on some models, and streaming if you use an NVidia Shield.
B. Part 2 VRAM: In order for GPUS to function properly, they need to have their own vram (or memory) so they can store all the textures, frames and other necessary properties to get frames to your monitor.
It can be tricky to figure out how much you need because you have probably seen GeForce GTX 870M and 880M with 4GB or 8GB of vram. I'd suggest getting as much vram as you can, though having 8GB isn't that all necessary, as long as you have 3-4GB of vram you will be good.
However, for you budget gamers, a GeForce gtx 850/760/860 with only 2GB of vram is also ok as long as your resolution is at 1080P, because those gpus are not powerful enough to play at ultra, so it will use far less vram to play at medium-high settings than ultra.
C. Resolution: As you probably seen, 1080P has been the norm for a while now, however you probably have seen newer 3k laptops out aswell.
3k will give you a lot clearer picture, so if you desire a very clear image, 3k will best suit you. However, in order to drive 3k, you want at least a GTX 870/880M for 3k gaming. Since 3k is basically 3x 1080P resolution so the graphics processor has to work 3 times harder than before. So you will need a costly gaming machine to do this.
1080P can both be cheaper and better depending on what kind of gamer you are, if you love extremely clear eye candy, then 3k is for you. But if you want FPS over eye candy, 1080P I would still recommend because it is both cheaper and the gpu doesn't have to work as hard so you will get a lot higher frames per second.
D. RAM or Memory: Memory is also crucial because the cpu needs to store all the game settings/files that it needs in the system RAM. 8GB is my requirement for intensive gaming, you can get away with 6GB but 8GB is about the same price and you won't come across any issues.
E. Drives: If your like most gamers that have 10-20+ games, your going to want a big big hard drive. Games of today usually require 5-10GB of storage, times that by 10 to 20 and that is a huge chunk of your hard drive consumed by games.
For this your going to want at least 1TB hard drive. I also recommend getting an SSD, even though you won't be putting games or at least not all your games on the SSD, the SSD will give you higher boot times with all the other thing you might do on your gaming laptop.
2. WHICH COMPANY?
There are many companies to choose from when it comes to gaming laptops, from Asus which makes heavy but very high quality metal laptops, to gigabyte which makes thin laptops to msi which does both.
This is all personal preference, pretty much all companies make good gaming laptops that are in this industry, so it comes down to what color you like, what design you like, and do you like a thin but hot laptop over a heavy but cool laptop.
I just wanted to also point out that if your buying a prebuilt laptop then you don't have to worry as much about most of things I talked about in the hardware part of this tutorial. However, if you are doing a custom laptop, then I'd not skim through my tutorial but take a look at all of it if you can.
Another fancy laptop you probably seen is ones with dual gpus, like the Lenovo y500/y510p and a Arous X7 gaming laptop.
I would also put this as a personal preference, because I generally don't recommend SLI because you will most likely come across both heat and latency issues. However, if you like a laptop that does have SLI because it doesn't have Nvidia optimus or some other reason then buying it wouldn't be a bad thing at all.
Thank you all for reading this! I hope this helps anybody looking for a gaming laptop.