Aircraft mechanicfag here.
I'm gonna be honest with you.
Most times when we do the preflight/postflight inspections, we top off the fluids, refuel, download the engine data, check the tires for cord and do a brief look over the rest of the plane.
Often times, when cord is showing but we're on a tight timeline, we'll use a black grease pencil to cover it up so we don't have to change it. That way if quality assurance does an inspection they won't notice it.
We also carry around "scrounge" which is pretty much just a pocket full of differently sized screws. If we notice that one fell out in flight, we go through the scrounge until we find one that fits. It may not be the proper length or material, but we make sure it fits.
If a nutplate has broken off and a screw won't stay in the hole, it's not uncommon for us to use a bit of superglue on the head of the screw to keep it in place and make it look good.
If there are lots of rivets or screws loose on the wing and we don't have a lot of time, we'll just wipe the black streaks off with a rag. Those streaks are the dirt and grime from under the panel getting caught in the slipstream as the screws are rattling, which forms the marks that run fore to aft. You can see them form during flight lots of times.
Safety wire is amazing. We use it to hold shit in places it was never intended to be. I've seen it used to stretch wire bundles to cannon plugs, used to hold circuit breakers closed, etc.
There are things called differential pressure indicators or delta-p's. They pop out when there's too much debris in a specific filter (typically hydraulic) and the fluid is forced to be rerouted. Replacing the filter is super easy, but the function checks afterwards aren't. Usually we just push the indicator back in while the system is powered down.
Sometimes if we are overworked and we know QA is on the prowl, we'll use a magnet to pull the delta-p out right before flight to ground the jet so we get a break