What you wanna strive for is to get the most amount of MS and this mastery page gives you the most amount of MS you will ever get in the masteries.
for summoner spells go:
revive and ghost
As MS teemo, you will run into their territory as a result, a slight mistake means death so that is why you take revive and the MS boost revive gives is pretty big assuming you use the masteries recommended. I think you already understand why we will take ghost.
MS quints are a must as you want as much MS as possible. Defence runes are a must as well because you will not get any defence in our build. You get armor per lvl instead of flat armor because you can survive early on as your enemy don't have their items yet but later on, they will hit you hard. Same thing for magic resist per lvl. Get flat armor reds as there is no armor per lvl reds.
items you get are:
1.boots of mobility
You get boots of mobility as it gives you the most MS and you will be roaming the whole game so you will almost always haves the secondary effect of the boots of mobility. Phantom dancer is a must as it gives you the most MS an item can give you. Shurelia's reverie and youmuu's ghostblade gives you a big boost of speed so when you are surrounded, you pop those actives, your move quick, and your ghost and watch as you walk right past them.
How to play MS teemo?
1.backdoor every time your enemy leaves a point open
2.when capturing a point and an enemy is coming, don't leave right away unless they surrounded you. Wait until the last minute then leave.
3.don't forget to roam
1.plant shrooms on shrines to annoy your enemy.
2.you want to avoid people who can stun and jump to you as your MS won't work if your stunned and people who can jump on you will just jump on you no matter how fast you are
3.you can annoy but you can't fight