This one requires extreme speed, but when it works, it's AMAZING.
1. Find insulated gloves and a full toolbelt w/ multitool; can be done by checking through Nexus dorms lockers for gloves, through supply crates found around the colony, or by shooting open a locker in the engineering pod.
1a. While it might take some time, I recommend getting power up, thereafter hacking the vending machine buried under metal foam above the geothermal generators for welding helmets. Since the extra vision doesn't really matter for a survivor, remember to have these down at ALL TIMES if you decide to do this. Only one generator is necessay, so don't burn your eyes out trying to fix the whole thing.
2. Hack open engineering's material storage closet, get the uranium inside. Start dragging around a SUPERPACMAN generator.
3. Find somewhere to dismantle a useless APC, like Fitness. Take everything with you.
4. You can either hit Nexus Storage now or later for metal. I recommend doing so later.
5. Transport your generator to tablefort, wrench it down so no xenoscum can steal it. Get the flamethrower, grenades, and pistol inside the marine belt to help yourself through the increasingly active xeno hordes.
6. Go back to the Nexus and into the cargo bay. You want to unwrench the tank storage unit because it has 10 plasma tanks, which means more ammo for your flamethrower than you'll ever use if you wield the weapon responsibly. Also get lots of materials from Nexus Storage, preferably metal rods and sheets.
7. Haul ass back to tablefort. You can scare away the crappy xenos with your flamethrower, and runners will still flee from pistol rounds at this point if you've got a welding helmet. Never use grenades on a runner, and ONLY fight defensively; get too aggressive and the xenos will start slashing.
8. This is the hardest part, because you have to balance defense and building. First, note that the lights at tablefort can be moved with a wrench. Use them as barriers, same thing with the tank storage unit and SUPERPACMAN. Because it only takes a spitter three hits to burn down grilles, I recommend barricading with girders first, grilles second.
8a. Make one girder into a full wall when you're fully secure. Build your APC. It will not be powered by the geothermal generators, so hook your SUPERPACMAN to the grid on top of a knotted piece of cable. Feel free to weld this back to a girder later for maximum vision with your flamethrower. Also keep in mind that the flamethrower's burst itself does damage, so feel free to overlay an already-present line of fire with a new stream of xeno-repellent.
8b. Loop this cable outside your girders, making sure to wear a fresh welding helmet and using the floodlights to your advantage -- remember, the goal isn't to kill the xenos, just to scare/wound them so that they can't interrupt you. Making sure that every cable is knotted, make grilles over every outside girder except the one you are using as your false wall. Since you have insulated gloves, it doesn't matter if you run into them anyway.
9. You now own a fort! Once safely behind your defenses, flip your welding helmet up and use the extra vision to spot incoming xenos. You don't have uranium forever, so use your SUPERPACMAN sparingly. At the same time, remember that it takes roughly two to four seconds for the generator to heat up enough to power the grilles.
9a. One of my favorite tactics is leaving the generator off, watching a xeno start clawing it, then turning it on and chargrilling the invader. Do this enough and the xenos will start focusing on marines.
9b. Once the coast is clear for at least three minutes, you can go get things like the grenade launcher from the crashed ship, which is extremely useful for dealing with ravagers later on.
10. You won't have enough materials to help the marines, but be sure to trade some of your amenities with them; I gave plasma tanks, a spare welding helmet, and a few grenades for some mines that proved extremely useful. Remember that later on, the xenos will be coming for you with abominations like ravagers and crushers, so use the marine to get what you need in order to fight them.
BEFORE:
https://gyazo.com/41b98dc22a9c3b109c531eeb22927015
AFTER:
https://gyazo.com/884f90134aec543e860cbad845f45318
A total of six xenos died assaulting this, but two were dragged away just as they died by an extremely clever hivelord.
"I'm a soldier, that means I'm the defendant and the judge."
haven't done this in months but it worked most of the time 
