Building your own PC is pretty darn cool; it allows you so much control over the product that you get, and can also save you a bunch of money. (Seriously; while some people exaggerate the amount of money you can save, it does generally work out a lot cheaper.) If you want to do it, then you’d better make sure you avoid these mistakes.
Being really cheap
No, it’s not exactly a good idea to spend too much money, especially where there are plenty of PC components that will do just as well as the most expensive options for about two-thirds of the price. Having said that, you really need to see this as a real investment. If you build a solid PC, you should get at least five years of use out of it before it becomes more prudent to replace it than maintain it (though many people get even more use out of it than that!). So don’t be afraid to pour some money into this thing!
Not enough research
Sure, you may have been recommended a particular component by a friend you trust. But there are probably going to be several reasons why it would work best for them but not for you. You really need to think very carefully about what you want the PC to do for you, and then research the components you need accordingly. For example, you may have been recommended a solid state drive over a regular hard drive. But have you checked out the solid state drive stats? Enough research may also mean that you realize how complex a task this can be, which may lead you to hire someone else to do it for you. This can be a smart move, too!
The more fans the better, right? Well, it really depends on how much electricity your PC is going to use as well as how much work you’re going to make your components do. There could be a point where adding more fans would just be superfluous and thus a big waste of money. Furthermore, there are the mistakes people often make with the orientation of their fans. Fans are mounted as exhausts as well as intakes; this is what keeps cool air running through the chassis. If you’ve only mounted intakes and completely ignored exhausts, then the number doesn’t matter: your PC is going to overheat.
Making alterations so a component will fit
So that graphics card you’ve bought is a little too big for the slot. Or the cooler you have doesn’t fit snugly on your motherboard or CPU. No matter though, right? You know that some people have actually gone DIY on this problem; they’ve shaved down certain parts or drilled a few holes here and there in order to make components fit. Yes, it would be disingenuous to say that this never works. But most of the time, it’s a bad idea, and not only because you may not have the skills to do it with finesse. Consult an expert to see if it’s possible if you find yourself unable to exchange components for something that would fit better.