I really like that second one. It's not looking like the sharpest shot ever, but sometimes that works well in a portrait.
If you wanted to *make* it sharper, a few questions:
What sort of lens do you have there?
And, are these scans of the negatives, or of prints?
The first thing I'd do is be sure the negatives themselves aren't sharper than your final results: the issue may be downstream of the camera. Sometimes machine-printers go out of focus a little, and it can look like that, even if the negs are very sharp.
In low light, issues may be steadiness, either of your hands or related to subject motion, lenses not being at their sharpest with a wide-open aperture, or a combination of factors.
Still a really good start.
As for cleaning, the videos should get you on the right track. If there's anything particularly sticky or hard to get at on the camera body, bamboo skewers are very useful. You can use the point to get in corners, and mush the fibers apart a little to make as soft or hard a 'brush' as you may need.
If the leatherette needs cleaning, don't use anything too harsh or soapy, or much of it. (What to use may vary depending what it's made of, and I forget what K1000s have.) Sometimes all it may take is a little light scrubbing with an old damp toothbrush, if it's gotten dirty in the texture.