Farm, dodge, poke, these three are the essential order that you should do things, get malefic visions up as soon as possible, while farming all the time. Late game with this build is awesome. Early game, never use any other spell than E and the occasional Q. When you cast E on the first few minion waves you will need to basic attack the minion so that your E can jump and refund mana.
Reason, wastes too much mana to use other spells too often, if you farm and poke with your E at the same time, and you played mid right, then you should have the perfect gank set up with the jungler because you have slowly wittled away your enemies life, bit by bit, they will most of the time still be in lane, just dont get greedy and all works out in the end. You will need to outplay enemy champs a lot if you plan on hitting every single E at the right time, go for the weakest minion first, never the siege minion unless your E is just that OP, then you can do whatever you want.
After level 6 you and the jungler need to push lane and use R to kill the mid, make sure the mid has half health or you have enough faith in your jungler that he is able to deal the damage required to kill or else your R would have been used at the wrong time. When you cast R you can cast the ignite while R is being used but only if the enemy is in range of you, cast W before you ult and it deals that extra damage needed to finish off the enemy. When you see your R timer about to end, get you Q ready and spawn it where you think they will be, then use E and you should be able to kill or extremely wound the enemy. The enemy jungler might come for a gank, just run away and if the enemy jungler camps lane, just farm and stay back, your E has a pretty large range. Your R should be used to kill or run away since it is a suppress. Unless the mid has a spell shield then you need to proc it first. I have gone against a lot of champions in mid and as long as i didnt get greedy my lane has held up fine.
After, push lane, roam if there is the chance, help top or bot, and always be in the team fights or heading to one. Your R is valuable and expendable if you have blue buff, use when you can if you have blue buff for the CD that it gives. Malzahar doesnt need blue buff from the jungler if you just use Malefic Visions and the occasional Q, because of the passive that E gives.
1v1 you should never die, you either kill them quick or you run away, always think of the escape when you go into the fight and think of escaping if your R does nothing to them.
At the start of the game, always reason with the enemy, "Gooby Pls", is an ample quote from the great Dolan as it helps with the morality of your team as well as demoralizing the enemy if said in all chat.