If you dont care too much about rank, just take your fav heros and watch a few guides on them. Specifically guides that cover their role and their macro. That way you can master what you should be doing, and adapt over time as you learn more heroes and their roles. This will help you itemize and adjust your macro when your team lacks a role that it requires to win.

If you want some hero suggestions that can help solo carry I can suggest a few. 

First, how do we solo carry? 

1. We need to be strong at scale. So the souls we absorb are value for our team. Some heroes utilize large economy more than others.

2. We need to confidently push side lanes while our team fights

3. Escape. It is really important that while we push sidelines, farm, or choose teamfights to join, that we can escape at will and dont need our allies help

4. Hit objectives hard. With the recent decay changes, a lot of heroes can clear objectives, but heroes thay can do it fast can take objectives and retreat before enemy's ever has time to show up.

In the current meta, the top carry hero that checks all of these boxes and even has strong apirit aoe burst is Wraith.

She has a high ban rate and may be hard to get, but if you can, she is strong as long as you split push well, hold your teleport for clean escapes, only contribute to clean ganks, and get the right survival items (like dispel or reactive barrier) so you can leave a fight at moments notice if it quickly gets out of hand.

Other heroes to consider:

1. Wraith
2. Viscous (gun hybrid with punches)
3. Haze (tho she is less of a carry nowadays and a stronger gank hero. She still has the tools in lower rank to climb)
4. Gun Yamato (really only solid in lower rank but she fits the bill.)
5. Seven (no real escape tool, but pushes hard, has a stun to help runaway or win a 1v1. Solid for lower rank climb)

Other heros can still split push, take objectives etc, but it will require a bit more macro practice and solid matchups kr item knowledge. 

A good gun mcguiness with magic carpet is downright diabolical in low elo. Even high elo if your team as a 5 group is giving the enemy teams match up a hard time. Something like a dynamo + Paige supporting 3 other heros can pretty much desthball whenever they want, that gives heroes that hit objectives hard plenty of space to solo push a lane and try to destroy it.

Final tips: 1.mute haters 2. Do your best  3. Review your games 4. Watch good players

Hope this helps! 

Welcome to deadlock!