I have 10 different accounts all in plat+ and 1 in Diamond 3.
When smurfing, its different in each elo. I actually kept notes for each elo of what to do when I smurf. Ill give them to you if youre interested.
Bronze-Gold:
Farm and win lane. Camp the enemy jungler, steal enemy jungler camps.
Gold-Diamond:
Farm and harass the enemy laner till youre level 4. Once level 4 keep harassing, push lane, roam mid. Save teleport for bot lane, never teleport top lane unless its about to be taken or there is 2 waves of minions under your tower.
Diamond+:
Setup ganks for your jungler for top lane. Win lane bot lane win game. Save teleport for bot lane. Try to gank bot lane at least every 6-8 minutes. Roam mid only if enemy mid laner is too aggressive, has no escape (zed, fizz, are examples of who not to gank), or if your enemy top laner freezes wave under his tower.
Hope that helps.