EPTI'm not saying this is a huge feat or anything, seeing as the game is constantly changing and the ranking system isn't the best out there but I do notice a lot of people struggling in the high ranks and the popular reason for why they can't go to the lower ranks is because of their allies.
This toxic mentality is horrible and will not help them to achieve lower ranks in the game. If you're about a thousand games in and you're still in the high ranks, trust me, there's a reason for that and it's not solely because of your allies either. I will first go over some fundamentals that I've seen high rankers lack.
Core Fundamentals
Being always aware of the mini map and the position of both your team and the enemies team.
Being careful not to face check bushes if you're a squishy character.
Not initiating battles as a squishy hero.
Not being too far into your lane if you're a squish character, specially if some of their team mates are missing.
Not taking dangerous routes when rotating.
Not trying to take vision by yourself.
Not using your heroic ability before a major team fight or objective, unless it's a guaranteed kill.
Typing in chat that the person in your lane has gone missing or "MIA"
That being said, I will go over my game play style and strategy i use to get to rank 1.
The first thing i do is that I always have a duo partner with me with voice communication. It doesn't have to be the best player in the world, but having one person that you can synergize well with helps a ton.
I like to run a roam and gank style with my duo ally while picking two heroes that syenrgize well with eachother to secure kills, I like to usually go with a Warrior, "exp: Diablo, Arthas, Muradin, Artanis, Anub" and a assasin, "exp: Jaina, Thrall, KT, Raynor, Butcher, Tychus, Falstad, Zeratul, Kerrigan, lin-ming, Lunara, Greymange. You could also get away with two assassins with you and your duo but it's much better if one of you is the Tank, because the tank is basically like the team captain. The tank is the one who leads the teams roam around the map, and initiate battles.
Be very active During the Draft. Try to suggest hero picks for your team mates that synergize with eachother. A lot of people are stubborn but at least try influence your team.
The reason why I like to run this style of play, is because it simply isn't enough to just play "Safe" in your lane. You must make some sort of positive impact in the game to bring some sort of advantage to the team. When you enter the game, you must step up to be the leader / shot caller and try to coordinate and communicate with your team the most positive way possible.
For example, before team fights happen, look at the cool downs of your team mates heroics and see if there's any missing, If there is, ping retreat and say to wait for whoever's cooldown to come back up. Before any team fight actually happens, you must tell your team to focus 1 hero and tell them who you want to zone in. Let your support player know, who they should be mainly looking to use their heroic on if they're someone like Uther (Divine Shield), rehgar (Ancestral Healing), Kharazim (Divine Palm).
There are two phases in the game, the split and soak and the 5 man roaming phases.
In the early game, people will be split to get as much experience possible. This is the time where i tell my allies to continue soaking each lane while my duo and I roam each lane to look for picks. Always be aware of the mini map and see which of their team mates goes too far into the lane. When you find a potential target, ping the person you're looking to kill as you're roaming to that lane. This lets the ally in that lane know that you're trying to gank the lane to prepare to follow up with you and your tank. Getting a lot of kills and getting to Level 10 first, gives huge impact in your team, because not only that you get xp for getting kills, you are also denying them of soak and you can potentially push in the lane and get a tower or two.
The other phase of the game, usually mid-late game, people will roam as 5 to do camps, and do objectives to look for picks. It's very important that you group all your allies together. What happens a lot in the higher ranks, 4 people will group up and one guy didn't get the memo and stays soaking a lane while your team gets 4v5'd. You must be very proactive in telling your team mates to group up.
Most games lost is because one guy gets picked off, and he's on a 40 second respawn timer, which leaves the opposing team plenty of time to get a huge advantage, such as getting a boss, killing a keep, taking your camps, taking objective or even finishing the game if the person they killed is one of your main dps heroes .
Try to synergize heroic abilities with your team and let them know what you're trying to do and try to group everyone together for objectives. If one person is missing, ping to retreat, the easiest way to lose the game, is to give the other team 4 kill experience, plus the objective because you fought a 4v5 and got wiped.
Hopefully this helps a bit and understanding a top ranked player's point of view. If you need some advise, feel free to send me a friend request, shenron#1478 and i'll play some duo's with you / or look at some replays.
-Shenron
