It's one of those things where you really have to push yourself mentally and understand how your mind tries to fool you into thinking you are at failure when you aren't. Muscle failure, from an evolutionary perspective, is life threatening. So if you feel that you have pushed yourself to muscle failure, and you're not getting good results, then you probably aren't failing yet. Two things that I did recently which has helped me tremendously: I started to ask someone nearby to spot me on the last few reps. I'd ask them to only use their fingers to assist. This forced me to struggle through it more. I think it also motivated me more psychologically because now someone was watching me. The other thing I did is lowered the weight. It was a huge blow to my ego but it made a big difference. That allowed me to focus on form and do it slowly. It should start out somewhat easy and then get very difficult after 10 reps. My time under load is between 1 to minutes. Reps are usually between 10 and 18. Some days I feel better than others but since I started exercising this way, I've been surprised when looking at myself in the gym mirror post workout.

Regarding gains translating to other areas, it just depends. Having more muscle typically has a universal benefit in other areas of your life. But if you're an athlete like a football player, you still need to train in that sport to be better at that sport. For example, a lot of football players do power cleans because they think it'll help them be more explosive. But doing power cleans only makes you stronger. You still need to practice being explosive on a football field for that. Hope that helps.