So you finally have decided to take on the task of building a PC, and you are most likely confused where the hell to start. Well, today's your lucky day. I'm going to give a quick run down on what you should and shouldn't do while going through the process!
Note: This is NOT a step-by-step guide to building your PC, just some tips to make your life a bit easier!

Stage One: The Build
This is the process where you begin searching for parts for your PC, and searching what parts will get you the best PC you can for your money!

Do: Set a budget!
Setting a budget is key! Never go up to someone and ask them to make you a part-list without a budget in mind. I always suggest setting your budget slightly above what you think you will need. So if you think you need a $800 PC, be prepared to spend $1000, as other things can come into play which will raise your budget, such as price fluctuation, sudden changes of parts or peripherals you may have forgot! A good guide to see how much you want to spend can be found here: http://www.logicalincrements.com

Don't: Assume the most popular options are the best options!
A common mistake is choosing brands which are popular such as Nvidia and Intel to name a couple. You must realize that sometimes they may not have the best price/performance for the PC you are building. A common example would be getting a 970, when a 390 is a better option in most cases. Read up on reviews and compare benchmarks including performance and heat (power consumption is not a huge issue; if you are dishing out over $500 on a PC, a buck a month more won't hurt you!).

Do: Wait!
Waiting is a key element of the PC building process. Whether it is waiting for a price to drop, or for a new generation of GPUs to release, it is always important. The worst feeling is buyers regret! That being said, be happy with what you have when you get it, and try your best to simply enjoy what you have and don't try to "Keep up with the Joneses!".

Don't: Overspend!
Overspending and getting an overkill rig is just another source of buyer's regret. If you are only planning on getting a PC for gaming on a 1080 monitor, there is no need to get SLI Titan Xs, or a 4790k. Make sure you look up benchmarks of the games you want to play, and buy parts that will match your needs!

Do: Order from trusted distributors!
Buying PC parts from second-hand sites like eBay and (sometimes) amazon, is never a good decision! For one, there parts are of course, secondhand. But the bigger issue is warranty. Buying from a distributor such as NCIX, newegg or microcenter is a fantastic idea since they often offer year long warranties on all their parts. You never know what kind of issues you will run into somewhere along the line, so you should always try to have a safety net!

Don't: Buy useless addons!
Buying things like an optical drive and sound card are almost useless in this day and age. Rarely will you need to use disks (of course there are exceptions!) and built-in sound on most modern motherboards sound about the same as a sound cards! Save some money, don't give into silly peripherals.

Stage Two: Construction

Do: Buy an anti-static wrist-strap and mat!
Often considered "not worth it", anti-static supplies are a fantastic way to ensure you don't short out your parts while assembling the PC. If you do not have the money to spend on these supplies, make sure you are touching a grounded piece of metal, such as an unpainted part of the PC case, or a table leg. Also don't try to take apart a printer while using an anti-static wrist strap, that will just hurt you. Just adding that in case you are stupid enough to try it.

Don't: Place your components or PC on a carpet!
One of the worst things you can do is place any sort of component on a carpet, simply because of the ESD contained in them! Not only that, but if you have your PC running on a carpet, is can very easily overheat if the carpet is like that 80s green shag shit!

Do: Follow the order!
This is preference, but I tend to follow THIS order while constructing my PC builds: Insert CPU and RAM and cooler (unless it is a CLC cooler) into MoBo -> Put PSU in case -> Put SSDs and HDDs and other drives in case -> MoBo into case -> Connect cables -> (Set up watercooler if you have one!) -> Insert GPUs -> All set!

Don't: Touch the back end of the CPU!
This is crucial! Never ever ever touch the back side of the CPU where the copper(or gold is), this is how you short your CPU, making it unusable!

Stage 3: The Troubleshooting

Do: Make use of your warranty!
If a part is at the point of no return, instead of getting rid of the part and buying a new one, check your warranty status! And even if it has expired, contact the company and see if they will send you a new one. Many companies like Gigabyte and EVGA will do this to keep your brand loyalty!

Don't: Attempt to repair the component yourself! (Exceptions apply)
If a part has broken, don't attempt to repair it yourself unless you know what you are doing. It can be very dangerous, and you are probably better off just taking it to someone who is trained in repairing electronic components. Taking apart components like power supplies, can lead to death from stored charge in capacitors.

This is just the start. I will be adding more and more as time goes on. If you have suggestions, just post below or PM and I will consider adding it!