A tip for Fiddlesticks
If a blink can cover more than half of the thickness of a piece of terrain, you will appear on the other side of it. This is most commonly used for long flashes, but you can use this for ganking as Fiddle.
Say you are standing at circle 1, and the circle around that is the max range of your ultimate.
If you place your targeting reticle at circle 2 (the extent of your range), you will appear at circle 3, in the lane.
You do not have to target the lane.
This, obviously, works in the toplane version of that terrain as well.
I have seen people needlessly waste ticks of their ultimate's damage because they ulted directly onto terrain, but had to take a few steps (or even flash) to get onto the enemy.
It really isn't hard. Turn on range indicators (or smart cast for R) and try it in a custom.
edit: Ok, it USED to be easy. Since the summoners rift update, and the slight terrain cleanup that happened with it, It might not be possible anymore. This... displeases me.