Oh i just remembered few more lol
5. Strafe. use that to maximum advantage. Of MANY uses, this can be used effectively to combat a dragoon even w/ just a rifle. When they do their specialty jump toward you, just strafe to the side and continue firing at the large target DUMMY, stranded in mid air. The dragoon will probably try to stomp you a few more times before running away. rinse-repeat till either it runs away too fast or he no longer moves much at all. It's not a sure-fire, but i've actually managed to fend off 3 dragoons and a dretch strafing and ALMOST killed one (oooh how i wish i killed it before it ran off) Of course, i dind't get a kill; i was trying to make my way back to base, anyways.
6. Sprint. When you chase a wounded, screaming dragoon, or if you are being chased by angry friends of his, make use of the run fuction. Go check out the key binds. I had to rearrange bunch of keys to fit my hands and had managed to fit the sprint bind to Caps Lock key. (FYI, my key binds are shift-crouch, q-use building, v-med kit, f-item, b-recharge/ammo, Caps Lock-sprint, alt-zoom) A drawback is that whenever i chat, i tend to type in capital letters lol
7. ....I had a 7... but de javu, i lost it. lol
[edit] Oh yeah. I'm not sure if this is true, since i havn't seen the dmg in numerical amount, but while playing as a dretch (btw, my fav alian lol), face UP, looking toward the target's face when you are at its feet! apparently, the game recongnizes this as a head-shot instead of a toe shot. I think about 2 good bites like this kills an unarmored human. Jumping for its head, on the other hand, is often the worst idea because it's too easy to shoot off a dretch flying straight towards the crosshair. You also lose all form of directional control while jumping, which means one just have to fire along your trojectory to litter a poor thing w/ bullet holes. At LEAST flank the human (ironically, jumping to his far left/right a couple of time actually helps, though using wall-climb to distract it is even better) before jumping for its head.
For those human-loving players, try to find a gun that you like best. For me, the fav set up is Las gun, light armor, helmet, battery pack, and optional nade. I try to stay away from close combat, though i can often hold my ground against dretches, dragoons, and marauder once i have a las gun and a light armor. (Again, strafe) (i have bit of problem w/ the White spider thingie, especially when it lands on top of my head...) I stay away from battle suit for the sake of radar and battery packs so i can fire more bullets and be able to spot them before they are behind me clawing away.
I do use jet packs especially when i'm assigned to base-defense.
I want to learn how to use pain saw more effectively (crouching seems to help A LOT against land-bound dretches) and envy those who mass-drive a dretch every shot. Flame throwers are known to get massive amount of cooked dretch, served either grilled or charred, though i've more often fried myself than dretches for some reason.
....Well, that's the ones i wanted to add :p c u all later
[edit]
with much thanx to those who contributed their thoughts to my post, i've added the following things to my list

thanx to all those who read and replyed (just a bit less thanx, but thanx nonetheless, to those who JUST read w/out replying :p)
so where was i... ah yes
8. Use blaster to earn your bragging-rights. For example, because killing a Tyrent with anything short of a Las Gun, and probably better off with something closer to a plasma rifle, is deemed nearly impossible, pulling it off in a fair fight (mono de mono) in mid-close combat WILL definitely either do one of two things; the player of the alien party will forever be branded as a noob of the year, or you will be deemed the most patient player (due to Tyrent's HUGE amount of health AND regen capacity) in the history of fps games (probably not in rpg standards though lol)
9. High numbers under the "ping" column means "do not play here"
Ping measures the speed in which a small packet of data is transfered to and from the server and you pc. more specifically, it measures the time in which it took to go there and back. so that means higher number is, in fact, very bad compared to lower numbers. (as opposed to the more conventional distance/sec measurements) So naturally, your actions, compared to those with lower pings, will be much slower and even out of sync; you might find bullets "hitting" the target in graphics, but not in actuality (provided there is such in virtuality...err). So do whatever is possible to lower the ping within the system by shutting down all internet-related programs (and other programs just to free up resources in general) before playing the game; you'll have much more fun doing so.
[edit]
10. Learn bind keys
I'm still experimenting on this (as in while i've binded few keys together, i havn't been using them lol) but i think it'll make a extremely efficient in many aspects of the game.
for example, tired of having to click click away in front of armory while others r quickly getting out, taking dretch kills? bind few unused keys (the entire spectrum of keys on the right side of the keyboard) to sell rifle, buy [ur wpn of choice goes here], buy armor and other stuff, so when u spawn w/ nuff money, u just press, say, [J K L] in front of armory, and u r out of there.
another example, and this goes especially for those of you who likes to play as a team, say u want to tell ur partner or the hunting crew that u r heading back for recharge/rearm ur ammo and heal. as for me, i do this a lot because i don't want them to find themselves stranded while thinking that i was backing them up. (i HATE it when they all leave me behind when battling...) I do try to let others know and find myself typing this away for like eternity, standing defensless. So binding such msg to another key would help communication a lot better and promote a team play, which this game is meant to be. For alien side, the obvious (unless u've been lucky so far) use of such immediate msg bind would be "NADE NADE NADE, RUN FOR UR LIVES" or something along the line lol
I also like to have one rifle player back in the base (rifle as in any prm wpn other than the kits) especially in a big game. This is not to camp but to discourage any lone, powerful, skillful alien from destroying our base single handly by finding loopholes in defenses. I've seen a lvl 3 human base go down by a lvl 1 alien team's lone dragoon. (no, i wasn't the dragoon, and yes, i thought someone deconed their base lol) If noone likes to do that, all high from getting kills off of seemingly fleeing aliens, i tend to do that myself and try to let others know. so "staying at base defense" or "staying rear guard" would by my keybind.
I think experimenting with binding overall would really help out emmensly for the game play :p