Re: What general advice would you give to a beginner, looking back at it
I say interpret nay sayers and nasty attitudes as objectively as possible. they might be spirit crushers but its entirely up to you how you want to receive such gestures, more often than not there is useful criticism and realities in these kinds of people... regardless of emotional baggage.
Go past your comfort physical boundries as much as healthily possible. If you do not look like a buggered dog walking out of there be aware you didn't fight through your training session. You will know who you are when you know your boundries. Then Set constant challanges - Little short term goals, mediums term goals and if you like boxing then make an overall picture when the time is right.
Gyms are full of people willing to spurt out information, beware the credible sources and those with a bit of wind up them. Copy the pros, forget the nice guy who likes a yarn after a session. Copy the successful people and take note from their example.
When sparring you'll pick up the skills from practise and coaching but don't take a beating to heart, there are some defeats more triumphant than victories. If it gets too much, theres always tomorrow.
Basically use boxing as a way to make a champion out of you personally. don't worry about the world titles or hbo, that is something entirely differant. A fighter is a character trait, use the gym is a means to express that side of you.