What you're doing seems to be working. So, keep doing it. When it stops, make the smallest changes possible to get it working again.
You've pretty much answered your own question here. Feeling the muscle seems key to making it grow.
Those people have probably been training for much longer than you have. What works for them now will quite probably not work for you now - hell, what works for them now would probably not have worked for them when they were at your stage.
Also, what exercises for each did you see them do? For example, doing light, slow high reps on squat is very, very different to doing heavy, high reps on leg press.