So you think you are good at DotA, but whenever you go to play ranked, your teammates end up feeding, or just sucking in general. If you support, your carrys are ♥♥♥♥, and if you carry, your supports are ♥♥♥♥. After reading a lot about getting out of trash tier, I tried some different methods and now use the ones that work the best. About 3 weeks ago I started to play and gained 700 mmr in those 3 weeks. This usually only works if you are better than your certain skill bracket, but if you are about the same level, you might make it work. Here is a screenshot of showing how much it works for me

Usually I pick storm spirit just because I like him a lot and find him a lot more fun to play and if you make a mistake (Wrong Positioning) you can zip right out of it, but if the opponent has instant initators (Axe, Magnus, ect) or a lot of silences. In that case I just get Templar assassin.

The strategy that works best for me is going mid. You don't have to deal with ♥♥♥♥ teammates feeding or taking your last hits. The 2 heroes I picked were Storm Spirit and Templar Assassin. I use these two heroes because they are pretty good early, great mid game, and can snowball from just a couple of kills. Usually if you are in trash tier, there will probably be a enemy mid that is trash too. For storm you probably want to get your first kill after you get your bottle, and maybe want to reach level 6 before going for the kill. With storm spirit you can usually dive the tower pretty well, and get the kill right when you reach level 6. A kill on storm spirit usually goes like this for me. Zip in - hit them once to use your overcharge, then use your electric vortex, hit again, use remenant, hit and then zip and hit a bit more untill they are dead. I am not going to explain everything about the hero, because there is tons of guides out there telling you how to play these heroes. On ta, I usually get a blink as my first main item (after bottle). Then build a desolater, and snowball from there.
EDIT: You can't really get an easy kill as soon as you get lvl 6 anymore after the storm nerf. Ofc if the enemy messes up or if you get a gank you might be able to get a kill, but it is much harder after the nerf.

If you have never played any of these heroes, then start playing them in unranked. Once you are comfortable with playing these heroes (for some it might be 5 games for some it might be 20), then start playing mmr with them.

At the beginning of the game when about 3 or 4 people are loaded on your team, you should say "Can I please mid?". You call it out before anyone else does, but wait for a few people so if someone else says who hasn't loaded in yet "Me mid" then your teammates will say "He already called mid".

During the picking stage, your teammates might be a bit retarded, so give them some advice. Usual comments I say are "Supports pick first please", and "We need an offline" or "We need a carry" Or "We need more supports". This way you aren't telling them a specific hero to play, which they might not be able to play well. Then they have a variety of options to chose from, and they will most likely chose a hero they are good with.

This is my first guide, and I hoped you liked it. I know I didn't go into much detail into playing the heroes, but learning heroes is one of the most fun things in DotA. If you are wondering for builds to use, use the "6.xx standard storm spirit build (Mid)" or "6.xx standard ta build (Mid)". Hopefully this strategy helps you get out of trash tier mmr! Msg me or comment if you need help with anything.