Surface Docking on Minmus
Landing to dock isn't impossible, but it is more difficult/costly depending on the amount of gravity of the body. On Minimus it's far easier/cost effective than say, on Mun.
Why? The lower gravity means you have more leeway in reaction times and the amount of fuel you have to expend is considerably lower too.
On Minimus, depending how massive your craft is, you might be able to get away with the entire thing using just RCS. On Mun, that's almost certainly not going to work and you're going to have to use the docking craft's main engines to null out the force of gravity.
At first, don't even think about doing it directly from orbit. That's almost certainly a recipe for disaster. Just make your initial point of contact close to your base and get everything stable.
Adding Docking Port Alignment Indicator into the mix helps out enormously.
After I make my initial landing near the base, I make sure my SAS is in attitude hold, then switch my control to the docking port facing downward. You should see the NavBall flip and rather than pointing up toward blue, it should be pointed down toward brown.
Next, make sure the NavBall is set to SURFACE. You want to make sure all your motion is relative to the surface, not orbit, not target.
Next, select the docking port on your base/refinery that is pointing UP.
If you have DPAI installed, you should now see the docking port indicator on the display and depending how OCD you are you might want to rotate your craft with reaction wheels or whatever so the two ports are aligned.
Last little bit of prep which feels almost like cheating, but it's an amazing help and since it's part of the stock game, I say it's fair game. On the NavBall, which is set to surface, and is indicating your docking port is pointing at the ground, select RADIAL IN. This will keep your craft more or less pointed directly at the surface. Depending on how much reaction wheel and how balanced your craft is in terms of RCS, you might wobble a bit, but if everything is cool and you don't over control with thrusters, it's an amazing help.
Now "all you have to do" is throttle up slightly to null out the force of gravity and amazingly enough, it's just like docking anywhere else.
Once you get this procedure down, you'll be amazed at how much easier it is that trying to dock purely visually and by guessing if things are aligned.