I'm looking to build my first AR and I was wondering what advice you guys might have for me.  Are there certain things to stay away from?

I recommend quality custom parts. You get what you pay for.  It's worth the wait.
 

Meh. I recommend Palmetto State Armory for your first build. They sell high quality parts at a great price. Shipping can be a tad slow to some but the money you'll save is worth it IMHO. And they will have everything you need to build an AR any way you want. Say you want a complete lower but you want to build the upper or vice versa. Or you can build everything from the ground up.


Eta: I also recommend getting the proper tools (punches, armorers wrench, etc). If you are planning on building more (you will whether you know it now or not) they are worth every penny.

The two parts that you don't want to go cheap on is your BCG and barrel. Buy from reputable retailers and manufacturers. Stay away from aluminum gas blocks.

Avoid Blackthorn at all costs.  They are cheaper than most, but for a reason.

Take up reloading - I just calculated my recent component purchases and I'll be reloading quality brass ammo for under a quarter a shot. It was not a huge cost to add .223 hardware to the other 5 pistol calibers I already load. In my neck of the woods, boxer primed brass .223 ammo is going for anywhere from $0.40 - $0.050 per round..The costs for extras dies and equipment to reload rifle will be paid back in the first 1000 rounds reloaded.

First, you don't need a bunch of expensive tools that take dozens of gun builds to justify. Read the stickies on assembly, so far the best tool I have bought is the "universal" armorer's wrench which actually isn't issue at all.

By parts for their specifications - not brand - because then you know what they are made of, why, and if they are at least milspec or why it might be better - and cheaper. I've gotten "msilspec" trigger kits from a known Brand and it needed a lot of finesse to get a decent trigger pull, and I've bought them for half the price in stainless and got twice as good a trigger.

Specs and features before Brand, bar none. It goes along with what the gun will be built to do, a 600m precision rifle build doesn't use the same parts, much less the same Brands, as a CQB AR pistol. And yet, they are both "AR's" on this forum.

Avoid race gun parts unless you are at the level you can see the difference in the scores you post at a National level event. It's your first AR, stick to the normal stuff, paying three times more and not being able to shoot it three times better is a real ego killer. Some like to build tricked out guns, and some can shoot tricked out guns, but very few do both.

How to tune the action is more important than picking cool parts and thinking they will go together. It means you know exactly why carbine gas doesn't work so well with a 16" barrel, or why it doesn't work so well with a 10.5" barrel but it's a better choice than pistol gas. Study gas port location and size - it's usually 5-7 inches behind the muzzle, not measured from the chamber, and how much gas is important in getting the cycle right - with that specific ammo. The M16/M4 is a good combat weapon because the ammo design is tightly controlled to produce the right amount of gas. Switching things up to some other ammo cause the most problems, cheap white box fodder or heavy bullets isn't what the AR15 does well. When someone suggests it should handle anything they put in the magazine, you just heard them out themselves and their lack of understanding.

Last but certainly not least, uppers and especially lowers in this market are a commodity from $39 up. Pick the roll mark you can afford that looks nice and accept that paying $100 more will not do a thing toward making it a better gun. The  other parts and how they interact will determine that.

I built my first one just a few months ago.

It's not as hard as you might think. Just go slow and double check everything. Plan it all out in advance.

You really don't need many specialized tools. Lots of handguards/barrel nuts are proprietary now, so you might not even need an armorer's wrench. I didn't.

As noted above - spend your money on the barrel and BCG. I would put trigger right behind that in pecking order of places to invest money.

Be sure to get a pivot pin detent tool!!!
--wheeler makes an inexpensive one and this $6 tool will save you loads of hassle and aggravation!  

For the pivot pin detent install I use a Home Depot 1/4" clevis pin and a small punch. Works great, costs pennies.

Only thing I have to add is use a good receiver block along with a good vice. Sucks to bend a receiver whether its a blem or expensive

Welcome  Spend a few hundred hours reading.  You will find most if not all of your questions answered here already.  Take a moment to read before asking the same question that gets asked 3-4 times daily.  Buy a membership...it will allow you better searching on subjects, plus you help support the site.  Everything you could possibly need is available thru one of the sponsors here.  There are other sources for your parts and doodads and you will discover them as you READ.  Don't buy a hand guard from ABC and then ask if it is any good.  Prepare to spend WAY more than you planned.  Now lock yourself in your room and research until your eyes bleed.  It is a disease.

Good luck man read and study everything posted here, and you will be fine, hey if I with no skills can build two of them so can you it's fun and easy did I say how much fun it was, lol I only bought a few basic tools a pivot pin tool a punch set and a roll pin punch set and I was off to the race, didn't own a vice so no need for a vice block just used a rubber mat and a block of wood, went slow and carefull, order an extra spring set you will shoot one accross the room like I did. lucky I had thought ahead and took advise and ordered extra detent pins and springs....
HAVE FUN

After you build your first, there's a good chance you'll build a second, a third.........

With me it started with replacing the handguard on my M&P15.  I just finished a 7.62X40WT, making number 9.

Thanks for the great advice everyone!  I look forward to my first build.

get yourself 1 or 2 ets magazines.

I agree and I went this route myself. I've seen numerous friends of mine buy cheaper components to get a build done fast without having to save or spend a ton of money and no sooner do they get it finished and they are already either replacing parts with the ones they wanted from the start or selling the entire rifle and lose money so they can fund the one they should've built from the start.

Take your time and check out as many builds as you can. Check out as many companies components as you can. Sooner or later you'll probably find a style of rifle you like(Recce, SPR etc) and you can start choosing parts based on that. A few other recommendations------1)Don't skimp on the barrel or bolt carrier group. 2)Get a 7075 mil spec buffer tube. 3)Get a quality trigger. The ALG ACT is good quality for a reasonable price and is the bare minimum Ill put in any rifle of mine. If the price doesn't scare you off, get a Geiselle 4) PMags, Lancer, Brownells and D&H are all good quality magazines