Dear laners: Stop showing the jungler you know he is going to gank
As a jungler, a safe-playing laner is still a target when recklessness allows opportunity for me to gank a lane. Waiting for 20+ seconds for a kill is worth it in my mind as long as I'm not waiting ridiculously long. But..
It helps so much when they throw a spell at me while I'm in the bush
It does little to no damage, tells them "Hey, I see you!" and displays their cockiness "haha I know you're ganking" which is incredibly useful for me. I will just gank from the side or another bush since they think they have scared me off, or I go save myself some time and go farm when you could have pretended not to notice me and starved me of gold and both me and your laner of experience.
What to do instead
Pretend you don't notice the jungler. Keep throwing spells at your enemies, stepping nearly out of position, but not quite. Look risky, but not at risk. When the jungler heads away, do something riskier but yet nothing stupid.
Waste as much of his time as possible
He is a jungler. He has less resources available than a laner, so he is thirsty for kills. You are the holy grail of gold. Instead of telling him to go away, pretend that you don't see him so he starves himself staring at you wishing he could kill you.