General Discussionself improvement need help from veterans

looking at your profile, you really don't play enough games.
1. Play alot more.
2. Spam hero's you have high winrates with.

On ur mmr lvl u should learn how to carry games on ur own. Dont hope in ur teammates. Play farming solo heroe (Mid/woods/offlane) and rape enemies.
Whenever u will learn how to rape enemies on ur own u will leave this braket.
Be incentive, agressive and smart. Thats all.

late game carries are good in this patch (spectre best), and also at lower mmr, you can just get good at like 1 mid hero and rise fast.
one good example is templar assassin. and also train last hitting, positioning and watch your enemy all the time (where they are, what items the have, what levels are they, where are they supposedly going). and also don't expect your teammates to buy wards, couriers, and also don't expect them to help you, cuz at lower mmr people don't react or sometimes simply don't see where you are and what you are doing.
gl nigg

u asked for improvement and not for gaining mmr

my recommendations:
-press the random button every game to help you understand pros and cons of each hero from a first person perspective
-watch pro games, but dont just be the guy that stares at dendi the entire game. ask yourself why they're making certain decisions. i recommend turning off sound because casting is annoying
-work on lane mechanics
-utilize minimap as best as you can. if 5 people are missing, ur probably getting ganked or roshans going down. if everyones on the map, then you're safe to farm
-try and be active on the map
-enjoy yourself

As a currently serving Army Reservist with less than 3 years of not-for-training Active Duty time, I do not legally qualify as a Veteran. But I'll still try and help you out.

If you have no idea what the pro scene meta is, then you probably don't watch pro games. You should change that; watching pro games will teach you a lot about sensible team composition, hero synergies/counters, and what is "good" right now. You have to adapt strategies to your level (solo queueing at 3k will not provide the same level of coordination as a professional team) but it's a good starting point.