4. Die less, kill more

This may seem obvious to anyone who has spent time with Dota 2, but it cannot be emphasized enough. Playing Dota is like walking on a frozen lake in the first week of spring. Sure, most of it is probably still pretty solid from winter, but you never know if the ice is going to break. So you proceed with caution.

Proceed with caution. Dying is detrimental to your team's success, and if you're going to die, make sure it's for a good cause. If dying enables your team to win an important team fight, it was definitely worth it. However, if you died crossing the river, just to nab an illusion rune, you are greatly decreasing your chances of winning and increasing your MMR.  

So, buy wards, call out when heroes are missing from your lane, and for the love of God pay attention to the minimap. If the enemy is missing completely from the map, don't go out wandering by yourself just to kill a neutral for 20 gold because chances are you're about to get wrecked.   

This doesn't mean you have to play like a scaredy cat. Killing is after all an essential part of winning a Dota match. Communicate with your teammates to set up devastating combos. Organize ganks on important enemy heroes. Buy smokes and find their jungler. Just always remember to proceed with caution.