I am here to offer advice to new builders and maybe some slightly more experienced builders, but the aim is for first timers.
1 - Price must include OS.
Unless your going to use Linux or your pirating Windows (Which I and am sure Tek Syndicate as a whole do not support) you need to remember to add Windows in, good luck using a PC without an OS.
2 - Non-K is good.
If your just starting out, I do not recommend overclocking at first, of course we here on Tek Syndicate will support you as we have many experienced OCers here, but I often give less computer savvy people the standard editions of CPUs, they work fine for them and will last a good long time.
This also applies if you do not wish to OC at all, why spend the extra cash?
3 - Look for open box.
Reputable retailers of course and I don't particularly recommend online ones, allow me to explain.
I live in the UK, we have a supplier called CCL Online, if I need parts extremely quick I use them, they sometimes have parts called "Open box" parts, these are returned items, the box has been opened but are generally included with cooler and a new warrenty provided directly by them, I can go in store or call them and ask about it as they can physically check the stock for me.
This is why I don't recommend pure online retailers, they may not be able to check the stock for you.
If you have the ability to go to the store and check the items like I do, get these cheaper parts, you can save some cash for that mt dew for them long gaming sessions.
4 - Never be afraid to ask questions.
I learned a lot by asking questions, some very silly ones, we are here to support you and give advice, even if you think its silly we can help you, and I expect people here are grown up enough to respond correctly unless its all part of a joke.
5 - Never pass a good deal.
Never pass a good deal when building, trust me, I got a R9 290 for £217 last year, I was extremely happy about this :).
Second hand parts are a brilliant also, I almost ended up with a Xeon server for a gaming machine, had the CPU, ECC RAM and 2 HDDs RAID ready, but I had my i5 already.
I would have got that for around £200, and it was a quad 3Ghz chip.
To people who have never used eBay before I recommend against this, but if you have someone experienced with hardware and knows how to shop on eBay, you could pick up a really powerful part for pennies.
6 - Plan the build.
Planning is very important, more than one would think.
Is your PC for gaming, VMs, Video Editing, Folding, Mining, Web browsing, let us know at the start of a question for builds and we can identify parts to a finer point over a general overview of the PC so example would be.
"This is my first PC build, It will be for gaming and video editing, I have £££ to spend", from that we get a good idea and can start firing ideas out.
7 - Post Dem Glam Shots.
We always like to see a new builder build their first PC, share you experiences and troubles with us and we can assist you further.
8 - Finally, enjoy.
PC Building has given me many hours of joy, so has repairs (I love hard drive recovery most), its a learning experience and enjoyment as you watch your new electric baby grow from parts in a box to a monstrous machine pure power, and when you have finished it should continue to give you joy with what ever it is you do, be ready for the time where repair time may come, but remember, we are here to support you, I very much doubt there is something we haven't come across as a community.
Enjoy the PC Master Race!