Eat enough food. Protein being the most important to focus on. Carbs and fats are generally easy to get in good quantities.
Sleep 6-9 hours a night depending on your needs. I do fine on 6 hours a night, but I sleep 9-10 hours on the weekends.
Train hard. Focus on the big basics and add in isolation after the fact for rounding out your physique more.
Train more rather than less. Learn what your limit is. People throw around the term overtraining way too much nowadays. Any one of my friends that competed in high school and college sports would laugh at what many consider overtraining on this board.
In highschool I trained 5-6 days a week for 1.5-2 hours. Typically 3 exercises per body part for 3 sets of 6-12 reps. Most all sets taken to momentary failure.
I stalled after about a year, but I never lost strength. Many years later and I realize that I was not eating enough to fuel muscle growth and weight gain as I could not break 167lbs back then. I can tell you I did not feel overtrained and only ever even thought about that when I started reading all the Arthur Jones and Mike Mentzer stuff which imho has so many people so paranoid about training too much that it's done as much harm as it has good.
Stay consistent and keep at it. If you have a day that you just don't feel too hot, get your ass to the gym anyway. I've had several kickass workouts where I felt like crap all day only to be invigorated by the workout. But, sometimes you still feel like crap. So what. Lift 75% of your normal weight. Do something. Go to the gym. I have to remind myself of this daily as I have had many bouts of inconsistency or just plain didn't lift for months. Over the many years of on/off training I've probably lost a good 3 years of training progress. Don't let this happen to you. Keep going. Keep playing. Be thankful you can even train.
Don't skip cardio. 3-4x a week of low to moderate intensity cardio will not hurt your gains if you eat enough. Infact it will help with your endurance to do more in the gym. You will utilize oxygen better and get better pumps and recover faster from workouts. Just don't go too hard on the cardio. If you make it anaerobic then that can negatively impact your performance when lifting unless your focus is to have a powerful anaerobic capacity and a good amount of muscle. Nothing wrong with that. If maximum strength/muscle is your goal, keep the cardio moderate-low intensity. It's good for you, kinda like tai chi.
I used to hate cardio. Now I realize my error.
Experiment. Try every exercise under the sun. See which seem to hit your muscles better. Lately I've come to realize that lying french presses just don't do it for me, but I love heavy weighted bench dips, close grip bench and overhead rope pulls for triceps and omfg, kickbacks. Figure out what works best for you.
Just my opinions.