Play lane normally up until lvl 6. The moment you reach 6, push your lane into tower then enter enemy jungle and ward it up with trinkets and shrooms. Return to lane and repeat process. This build is meant for pushing and running away, NOT FIGHTING. By using proper vision control, you shouldnt die. Items provide movement speed, wave clear, CDR, extra pushing power and vision. In early LvLs, use fresh blood, greenfather's gift and thunderlords to win trades. After LVL 6 the tactic begins, and you avoid fighting. Control enemy jungle, take their camps, and perma-push. If you see anyone coming(thanks to your vision control) run and go invisble somewhere safe using passive. Once its safe go back to pushing. The enemy should not know about your whereabouts except when pushing. Use your oracle and control wards to get rid of enemy trinkets. The enemy jungle is your domain past LvL 6 for the rest of the game on the side you are pushing. Once you take down their inhibitor, you switch to bot lane and repeat process.

Notice runes and masteries they're leaning towards movement speed and CDR.
If the enemies buy oracles and get rid of your shrooms you can replace them because you have CDR.
All 3 builds require testing.
All 3 builds( including runes and masteries) provide around 43% CDR. They all provide varying amounts of movement speed. They all have SIGHTSTONE.

As much as I love teemo and even though I have over 200k mastery points on him, I have to say that teemo is one of the most useless champions in the game(currently). The new oracles can disable your shrooms, and his on-hit builds are now weaker ever since they changed rageblade. The truth of the matter is, it takes a lot of effort to be useful on teemo and to consistently win with him. He provides very little to the team. Think about it, would you rather have a jayce or a teemo? Malphite or teemo? Kennen or teemo? Every toplaner being played currently provides much more than teemo. Even if you manage to win lane as teemo, your opponent will still be more relevant than you are, i.e its much more difficult to snowball as teemo now. Plus teemo has a lot of difficult matchups.
well since thats understoond, its time to embrace teemos uselessness. The guide above is simply a splitpush tactic like tryndamere but with a little twist. Lets explain tryndamere. Tryndamere is a duelist champ designed to splitpush, if anyone trys to stop him he can A. Run away using his spin or B. kill whoever comes and continue pushing. With this teemo, all you have is A. run away. But as I explained before teemo is useless therefore he has a low value. Whoever comes to stop teemo is probably more useful and therefore is more valuable. Basically your team is left in a 4 vs 4 situation which is much better than a 5 vs 5 situation since teemo is the most useless one on both teams. So basically the whole idea is applying pressure and hoping your team will win the 4 vs 4. One can say why not push and then if someone comes to stop you, roam to your team and make it a 5 vs 4? Well the reason is this build is pretty bad for fighting and you will probably die and theres a big chance that the person who came to stop you will roam down after he pushes out the wave and make it a 5 vs 5. Teemo doesnt have engage so he cant force fights. You roaming usually ends up in a 5 vs 4 dance until the enemy's 5th member comes back. If you leave to go back top to push, the enemy can force engage because they noticed you are gone and they can fight before you can reapply pressure top. This last sentence is the biggest reason why you perma-push. The key to this tactic is when you notice someone coming you run into their jungle and hide ( place shrooms, ward, take camps, or just go invisible) until the enemy is done pushing. The enemy will probably push that one wave that is crashing into his tower and then he will roam back to his team. The second he leaves you instantly return to lane and start pushing again forcing him to come back. And if hes stupid and doesnt come back you take free tower = WORTH.
Another important thing to note is that you are providing insane vision. You and your team can make picks especially if someone steps on a shroom.