First, you can predict for sure where the minions will be in the next 30 seconds with some experience.
If two nearly equal waves of minions collide, the one with a slight advantage will slowly push. If this happens near a turret, turret will help bounce it back for the next wave. The fewer minions were defending turret, the longer the bounce will be.
Extreme case: If you send a full minion wave to a turret by shoving enemy minions, the wave will end up in the middle, which is normally beneficial for your laner.
Predicting in a 1-3 minute timeframe is harder, but doable.
Basically you have to learn which champions can shove lane and which ones cannot, and whether it is beneficial for them to do so. For example, against yasuo it is beneficial to freeze your lane just outside of your turret range. He will either be forced to lose cs or overextend and try to play aggressively, exposing himself to ganks.
Also champions have their level and item powerspikes and want jungle assistance around these points in the game. You should watch allied and enemy champions and their items to understand what they are trying to do: just freeze the wave to farm safely or set up a gank.
Hovewer, in low elo this is not exactly true, and can be fairly random, sometimes the rule of thumb is just compare waveclear potential of every laner and assume that they push 24/7.
