The first thing to do is realize there is no end point. There is no finish line, so we don't need to be in a huge hurry or be in a great rush. Start working, and keep working, and just focus on getting better.
Second, check your ego at the door. Training is about getting better and working skills and tasks that we are not good at, not "winning" or getting the submission/throw/KO/whatever. Those are nice, and a good by-product of proper training, but not the most important part. If our partners are much better than us, trying desperately to catch up and somehow beat them can lead to the wrong path and injury. I have been sparring against my coach for 22+ years. I still have not beaten him in any measurable way, but that is not to say I am not substantially better than I was 22 years ago. My goal cannot be beating him, it must be on getting better at the little things along the way.
Third (and this can be the hardest one) is to make sure you don't train with douchebags. Don't train at a meathead MMA gym, or against testosterone pumped young ones who think that they must beat you at all costs. My gym has a reputation for hard training, but no one ever gets seriously injured, and we literally are a family. But my coach has gotten rid of all the douchebags, and all the new people come through me, and I either teach then the right mindset or they see it is not for them and they find the thug gym.
Lastly, don't be afraid to push yourself to train hard, but also be willing to coast at times. Maybe sit out a round. Or go really light. Do some rounds with easier partners like lower belts or smaller people. The caveat to that is then you must be willing to give up all physical attributes that would allow you to dominate them (see point 2 above).