I had (have) a meniscus tear in my left knee, pain is exacerbated by my work as a finish carpenter. I do all I can to protect my knees, using knee pads, and sitting rather than kneeling when possible.
My physiotherapist and personal trainers both recommended stabilizing excercises, as well as not pushing for max weight or reps in the gym.
For excercises, single leg squats, as low as possible before your knee starts to destabilize (starts wiggling back and forth), while standing on a bosu ball.
LIGHT single leg press.
Resistance bands and side stepping.
And the one that honestly helped me the most...the exercise bike. Motion is lotion. Getting blood flowing and using the joint, in it's comfortable range of motion, does wonders. I do 10km on the bike as a warm up for the gym. Increase resistance as you can comfortably, change seat heights to change the range of motion.
Back bridges helped too, as did using slides to just straighten and flex the knee joints.
I also used an elastic knee brace for a few months, which helped a lot.
Also worth considering is your daily footwear. Good supportive shoes, that don't have broken down soles or insoles help a lot.
I got fitted for custom work boots, and went from a size 10.5 off the shelf, to a 9.5 extra wide when the boots were built for my feet. That helped with the pain as well, actual proper fitting boots.
Hope it helps, having shitty knees sucks.