bonus: took me 8-9 months of working out to achieve this
also thanks bro @lume. I set the same goal for myself this year, to get bigger some more. It gets easier after you've been doing it for a while, just gotta get in the habit.
What kind of equipment do you use and how long would you say you work out each day?
My workout + more info about gaining muscle etc. for anyone that wants to know
I try to stick towards body weight exercises when I can because the kind of weights I use by now are scary to be around without a spotter, and dumbbells are pretty expensive, however I did buy a pair of adjustable dumbbells, that I use for some exercises, and they were really worth the investment. Like 8 bucks at wal-mart. (200 lb/90kg is my 1 rep max bench press for a 145lb/65kg kid)
Also the body weight exercises help with balance and gymnastics is one of my hobbies so they help each other quite nicely, and if I stick to my new years goal of learning to breakdance it'll help there too. The equipment you use doesn't matter, as long as you use it correctly you will see results (however they all have different pros/cons, and bodyweight have their own cons too, i'd suggest googling them to get an idea)
As for the amount I work out, it depends. I like to change things up to keep myself from getting bored, so one day I might have a 30 minute workout because I go through all my exercises with little to no break, while the next day it might be an hour because I'm doing an insanity asylum workout video. However my most typical exercise session is probably around 40 minutes.
My workout + more info about gaining muscle etc. for anyone that wants to know
Also if you do begin working out, don't skip leg day. Not every day is upper body day