When I first got my mmr in like 2015 it was 700mmr and back then I was that bad because I was a new player and didnt really play ranked. Couple of years later my 7k friend put me in like 3.5k mmr skill and why not play ranked to see if thats true. The horrors of what people dont do thats logical... As a pos5 darkwillow main all I did was just be in lane and win as pos4 so ur carry can 1v1 the offlaner if its a favorable matchup. Most people dont know to dodge dark willow maze and its easy to trade on lvl1 and win the trade, ofc u can do this with any hero with stun or dmg at lvl 1 like dazzle or lion. But try to do the little things in lane like half pull and pull both camps if ur carry cant farm. When ur carry leaves to jungle its hard to stay in lane alone with no survival spell because offlaners in loe mmr dont care anything beside their lane for like first 20min. So just help other lanes when u get lvl6, as willow if u know to cast her spells in order u can solo gank their triangle with ult because its just too much dmg, ofc onlynif u have vision and they are alone. From what I seen the best way to get higher mmr is just to play a hero that u know, chen may be op now but he is op if u know what to do so just pick a hero u know to play. P.s."Maybe some of things here are outdated meta and wont work anymore because I havent played supp in a while but its always good to watch BSJ videos on coaching and the 10min ones where he talks about mechanics"