I love working as a tactitian (SP?), and I usually send small amounts of people in groups different directions. A great strategy is to "leak" fake information and pretent it was supposed to be in team chat, to lure someone to another place.
Protip: When you're out of blocks while building, hold a grenade until you die, then go to the structure.

Great posts guys,they've all helped tremendously! I've used flanking to great effect; I can generally get at least 2 or 3 picks before I inevitably get sniped. I've also used one way tunnels as some fairly good sniper outposts for blue, although it's more a help to my team since I'm a horrid shot.

One tip I want to give is to build one way bunkers. Basically, instead of building a four walled bunker, you build three, with the side facing your spawn completely open. This make you vulnerable to flanking, but it ensures that if the bunker is captured the enemy will have to waste time building a wall, or else the bunker is completely useless to them.

Keep these posts coming guys, and thanks for all of your help!

To improve the "fake intels"-idea: add both upper and lower white triangles to your real intel. Now go on and build many fake intels also with both white triangles.
Now your enemy can't find out which one is the right one because the white triangle doesn't disappear on the map while moving up or down.

I try not to get shot. Works well.

Tips:
1) You can draw colored(yellow is best,or lighters shades of color) numbers to act as regroup points
2)you can dig a 2 block deep 7x7 tench and fill it with intel color and then surround it by bunker/tower
3)you can surround your intel with visible colored blocks and dig a one block deep pit on intel(only good against non diggers)
4)Build a spider tower on intel against diggers(best for blue) with long supports with a dug out base where the position of the intel sits for easy spotting of diggers surfacing
5)To fill up tunnels you either have to fill up the entrance in the case of straight and fill,get a bit creative for tunnels that L or Z and fill the corners and dig in another direction so as to not connect with the continuing one
For large tunnels is best to fill the entrance and build decoys with filled grey blocks
6) on some blue tunnels you can build death traps by digging straight down

I'll let ya in on my favorite.

I first take the safest, quiets route to get behind the enemy spawns.
I then dig into the ground hills/mountains behind said enemy spawn, basically rabbit tunnel and pop open an opening and pick off the enemy as they are either building/spawning or what have you.

After a few kills, close up the hole and pop open another spot somewhere else.
This is all done while crouch to reduce noise and to keep hidden.

The whole back spot can be riddled with rabbit tunnels.
I'll usually grab 10 kills minimum using this method.

Though it doesn't last forever.
The longer the game has been, the harder it gets.

my favorite strategy, albeit one i use rarely, is to pick a small spot near our intel,make a camo bunker, and snipe the enemies going rambo on it

I like being a tunnel rat. I crawl into the enemy's tunnels and eliminate anyone inside them. Although i take care of an immidieate threat the enemy can always go back in them. I try to destroy defences, but i usually get shot... 2 man team?

I Rambo it up in here. it usually works... usually

tunnel behind and pick 'em off, works every time

Yes, some people make green/blue squares(I think that is what intel looks like on the map), so people get confused. One server I was one had like 10, pretty funny stuff

I usually try to take out there structures mostly close to their base and also I heard this from the creator or something that people make fake intel rooms or something which sounded pretty hilarious

I used to sap the enemy's structures, usually from far away with the gun, especially small bunkers. Every now and then when I get to the base, I'll usually do something, like knock out a couple supports, or all of them. Now, I just build small bunkers and shoot people, usually not very long ranged, kind of just normal shooting, I guess.

One time, my team and I took down a mountain that had a lot of the enemies' stuff on it, which was pretty fun. I think I have seen a server where this happened a lot

I generally take the path to the enemy's base with the fewest amount of teammates there and flank the enemy from behind or to the side and snipe them while they are distracted by my teammates in other parts of the level.

My favorite strategy is to spawn behind enemies immediately after they kill me

I just downloaded AoS today, and after several hours playing on a 5v5 server I'm convinced that it's better than mine craft PvP in almost every single way (with the exception of booby traps, which may well be uploaded in an update to this game anyway). However, being new, I have fairly limited knowledge of the tactics and strategies in the game. I've read through the wiki strategies, and they certainly help, but I know this game can be more in depth than digging a tunnel to the intel or building a few camouflaged foxholes. I'm probably not alone in this camp, so I think it would be to the benefit of all (especially noobs like me) if we could share our strategies and tactics we use to everyone, from the most complex to the seemingly obvious. I'll start with one strategy my team used fairly effectively against the green team(I apologize if this is a well known strategy or one on the wiki I missed):

When the game begins and your on blue, head to the far flank of one of the maps and follow the edge to greens intel. Odds are they're still building their defenses or only 1 guard is posted. Sweep in, grab the intel, and make a mad but relatively safe dash to your base. If you get sniped, just come back and grab it again. Even if you only barely drag it five feet, just keep the pressure on and keep them from getting a base up. Once you get back to your side, you should have an easy time capturing it, although a last second push by green could still stop you.