When you teach, you learn.

There are many ways to get better at lifting (or any skill for that matter). You can practice it, read about it, listen to lectures about it, but one of the best ways is to teach it. In addition to your own training, you should make time to educate others. This is usually broken down into two parts: coaching technique and answering practical and theoretical questions.

Coaching technique

There is no substitute for real time coaching: watching a trainee move, comparing their movement to the ideal model in your head, communicating corrections, watching the effect of that communication, and using that feedback to modify your teaching. While this might sound like the only person getting anything out of the coaching is the trainee, you will get much more out of this than you realize. Watching deviations from an ideal model will make you realize aspects of your own technique that are deficient. Additionally, you will be able to synchronize what you're feeling in your own lifting with what you're seeing in your trainee's lifting. This is extremely important, because very often people do not know what they look like when they're lifting, and when their lifting deviates from their ideal model (much more so than they believe). This is also why videotaping your lifts is beneficial in making your lifting technique better.

Answer practical questions

Throughout the lifting session, a trainee will have questions, some of which you have thought of and must articulate and others which you will have not thought of and can't answer. If you can't answer them, finding out the answer will benefit not only them, but you. "Why does my elbow hurt?" "Should my thumbs be over or under the bar?" "The bar keeps slipping down on my back throughout the set. What's going on?" These are all questions that can come up during training, and being able to answer them will help you a lot in your own lifting.

Answering theoretical questions

Constructing, refining, and explaining an ideal model is part of any activity where consistency and effectiveness are required. Think of a time lifting (or in some other aspect of life) where you asked the question "Why do you do it like that?" and the person shrugs their shoulders and says "I don't know. I just do." or "that's how I've always done it." While their method may be coincidentally correct, it's far better to understand why you do what you do in order to best tend toward the correct answer. Without a doubt, at some point while coaching a trainee, they will ask you something to the effect of "Why should I do it this way?" and as the same with the practical questions, you should be able to answer that question with a concise and easy to understand explanation. Or you don't know the answer, which is normal too, but you should find out the answer. Refining and explaining the ideal model by which you train is key to getting better, even if your goal is not to become a strength coach.

All of these concepts can be applied to technique dependent skills in life: woodworking, Brazilian Jiujitsu, yoga, underwater basketweaving, everything. None of the advice means you have to quit your day job, start a business, and become an expert in the topic, but every time you teach someone how to do the thing you do, you will learn something. That will make you incrementally better at that skill.