how i learnt (which may not be the best way, but still) was simple.
firstly, i played about 100 co-op bot games with my friends (some who were playing since WC3 days) before stepping into my first public matchmaking game. now, this seems like a lot but the reason this helped me so much is that my friends weren't as pressured to win (it's pretty hard to lose against bots) so they were a lot more forgiving of my mistakes, and could spend more time focusing on what i was doing in the game
to get the hang of Dota 2 and it's basic controls, i played support. more specifically, i played a lot of Ogre and Drow. Ogre i played because it was a tanky melee support, on which i learnt all the mechanics of pulling, double- and triple-pulling, stacking and ganking. to be honest, it's quite a fool-proof hero. Drow was my go-to carry, which i learnt proper last-hitting, drawing creep aggro, and other carry-related mechanics. it's also one of the more forgiving carries in a low-level game where people aren't as sure how to deal with you.
so what this did was help me get a solid mechanics foundation before playing my first matchmaking game, and the lack of pressure in bot games means i was able to learn a lot better
BUTTTT you're already long past this stage so the stuff above could be better suited to people looking to start Dota.
from your Dotabuff i can see you favour playing core roles with high mid-game potential, with the possible exception of PL (the old version) and maybe Gyrocopter. one tip is to always carry a TP scroll, not just to defend a base or escape to safety but to punish aggression and tower diving. the low-level carry tunnel-visions on farming, other carries in the pro scene and high-level pubs have the game sense as to when they can join fights, even going so far as to employ the "1-protect-4" strat (a bit of an exaggeration but still)
this sense of when to join will be developed as you play more games as carry.
as someone who went through the insta-lock Slark/Razor phase (i see you've picked these two quite often), if you're playing them in the safe lane, you need to know that farming too much can actually hurt your team, especially if the enemy team has potential to go ultra-late game. get a sense of when you've hit the critical mass needed to join fights - a greed item like Midas pushes this timing back considerably, while a build like Phase/Treads - Aquila - Drums at a decent timing probably means you should fight with your team while you're ahead in items.
the same goes for some of your other favourite heroes like Jugg, SF, PL and Gyro. if the enemy team has expended crucial stuns to secure kills close to your tower, your TP in will either (a) scare them off (b) secure revenge kills. (e.g. Gyrocopter TPs in and immediately uses Call-down, prevents enemies from escaping and can secure kills with Rocket Barrage - Jugg with Omnislash - SF with Razes and Requiem)
anyway, some tips that you can hopefully learn from youtube to increase the efficiency of your offlane play (Clock/Axe/Razor offlane) are
(1) drawing Creep Aggro
(2) Dire Hard Camp pull
(3) effective smoke usage to make use of a good ganking rune (e.g. Haste/DD)
(4) EXP ranges - how close you can be to get EXP
(5) blocking the pull camps - unconventional ward spots
hope this helps!