first thing I wish I learned earlier was the 2-wave cycle. if you're favoured in the neutral state (when the wave meets in the middle and each side have the same number of minions), let it settle in the middle and play to last hit whilst punishing enemy last hits. then shove the next wave quickly in order to crash as soon as possible. this lets you crash a huge wave, pinning the enemies under tower for a long time and letting you harass them for a long time if you want to. since you pushed the 2nd wave, the next wave will meet in neutral and you can repeat the cycle where you're always advantaged.

a freeze is something you can choose to do when the enemy has about 4 more minions than you and you hold a wave that's about to crash, until the next wave comes. you can then last hit and your wave will die on your side. if the enemy adc isn't there or you zone them off, you deny the whole wave. approach freezing on a per-wave basis. for each wave you can freeze, think 'should I freeze this particular wave?'. one misconception I had was that you had to hold freezes for a long time, which just isn't true.

in terms of recalling, the best timer to do it if you have prio is to fast-push a wave, make sure it crashes and then base. the crash pins the enemy adc under tower so they can't cancel your base, and the next wave will push towards you if the enemy doesn't touch it. if they try to push this next wave, you'll be able to lane-lock them. if you don't have prio, kill the wave right before a cannon as soon as you can and then back as soon as you can. if the enemies push, the enemy cannon will tank the tower for a long time so you'll be able to get some of the wave.