Mistakes and other musings.
1) PR or ER, BtB's epic quote, is best left to the advanced lifters. Too many novice lifters get injured because they want to see a new number when their body is just not ready for it.
2) Eat right. This is different for different people. If you know you don't handle carbs well, don't eat them. This stays true even if some internet guru or 'roid brah from the gym tells you that you have to eat them to grow. However, if you can handle them, go for it.
3) You don't need supplements. I like them, but I buy very few any more. Once I run out of what I have right now, I will likely give up everything but whey and my vitamin/mineral supplements I take.
4) Get your form right. I doesn't matter how much weight you are moving in your first 3 months of lifting if you're doing it wrong.
5) If it hurts, stop. Don't be a baby, but don't be a hero either. The weight room is not the place for that.
6) Once you have the movements down, make progress every time you can. However, don't immediately begin using the 5RM, progress into it and your gains will be more steady and you will gain faster in the long run.
7) Work your back.
8) Work your legs
9) If you have a medical issue, be mindful of it and don't let other people pressure into exacerbating it.
10) Have fun. If you hate your routine, you won't do well on it unless you have a coach to push you. Find routines you enjoy and work hard.
11) Hard work is the most important factor. Work at your diet and your training and everything will fall into place. Get off the couch, get off the internet, and go lift.