I've played quite a bit of Warptorio, I really enjoy working in the confined space.
I play with a bunch of mods so if I say something you don't follow that's probably why.
I've stayed on planets upwards of 100 hours, it comes down to managing 2 things, biter evolution and pollution. Every time you warp biter evolution resets, I usually build a decent production line of artillery shells and park two artillery turrets on each corner of the base. When you warp in they'll go nuts and be prepared to have strong walls and defenses for the retaliatory attacks. They will however only be small or at most medium biters so easier to handle. This will initially spike evolution but it settles down until the pollution cloud over takes the arty radius. Ultimately it works in your favor. You can also go out and manually take out any other nests that are sending in attacks. Reduces the attack and you ultimately reduce the evolution. Pro Tip - get the "Jet Pack" mod it makes it really easy to get around the map quickly.
If you aren't already, get nuclear power going down in the basement. It's really hard to build enough coal powered electricity generation and impossible to do with solar. Just not enough room. This will also reduce your pollution cloud dramatically which reduces attacks and thereby Evolution.
Concentrate your harvesters on one or 2 resources at a time and stock pile resources (Warehousing mod is really good for this). Mine it and filter it as it comes in to the smelting area. Don't build stuff all over the map that you have to defend, it becomes to costly in both your time and resources. If you can, find patches well away from your base and build the harvesters there, clear out any nearby nests and they largely leave the harvesters alone as the concentrate on the base. Use the warp teleporter to mine Uranium (you can pump sulphiric acid out) or at oil patches. Again if it's far away it will largely be ignored and will only need basic defenses set up around it.
Move everything you possibly can underground and just keep the top level for defense. If all else fails you can retreat underground and warp out. Build a double row of walls on the platform backed with at least 1 row each of laser and bullet turrets (put lasers up front to keep ammo use down) I usually use the "modular turrets" mod as it gives a lot more options and range than vanilla does. Use Uranium ammo if you can as it hits way harder. If you need more defenses build dragons teeth walls with mines in the spaces (ie -x-x-x-x-x-x- where x is a mine and - is a wall and then offset the next row to create a checker board pattern)) do this 4 rows deep and up to 8 spaces out from the main wall. This will pretty much stop anything the turrets don't burn down or hold it up whilst they do. These outer walls are easily replaced when damaged, by bots and are easy to pick up or abandon if needed.
Other mods I find very useful
-belt boxes (crates to move stuff, very handy for through put on the central stairs)
-Omega Drill (when they uprgrade it to 1.1) you can easily fit to of these on a large harvester platform (yes you can overlap, it will warp as long as it is touching the platform) A couple of theses with beacons and productivity modules with belt boxes and you can move 8-10 blue belts of ore into the base easily.
Pro-tip. If you build a Spidertron, make sure it is not parked on the base when you upgrade the top platform, there is some bug that deletes it when the surface changes (bug report Pyro)
Good luck
