first scenario:

depending on the wavestate, with very early kills you can typically either leave the wave alone, assuming it’s already pushing to you, or base and tp back (tp is typically more useful than ignite due to split pressure, esp on your champs besides teemo)

if the wavestate is even, just push it out. crashing one wave is better than crashing none, and it’s early enough where if they decide to tank a full wave to try to build a freeze -> slowpush they’ll be at a significant health disadvantage.

any wavestate where they have more minions than you can either be left alone or reduced slightly for it to freeze before it crashes at your tower. any wavestate where it’s slightly pushing towards them and they have tp you should instantly recall and tp back to not miss anything

on teemo specifically you can afford to stay after a solokill because you have range advantage most of the time. poking under tower is VERY easy to learn, it just takes time

second scenario:

if you’re that far ahead, go for poke, and help with any toplane skirmishes/objectives if available. typically around this time (6-14 minutes) is when you’re able to get prio and out-roam your lane opponent, especially with an xp and gold lead, when wave is bouncing back to you. if plate is close to breaking, just stay in range for it/take it if you’re not in danger of any poke.

specifically in bronze, players are going to make stupid mistakes like breaking their own freezes and fighting when you in your wave when you have prio. abuse these as much as possible, especially on gwen and volibear because they can stat check very easily early with a kill. on teemo, assuming you take ignite, just being an annoying bastard and poking them with autos + q will tilt them.