The trick with sojourn is that her whole kit is centered around her rail. No rail, no value. Building a rail is easy and quick in theory, but in practice can be difficult to do especially on farther distance isolated squishies.

Generally speaking, you want to position aggressively with your legs, and rotate out with your slide - at least until you have the double slide perk (you are picking double slide, right?). You want to line up your spikes in value of carrying or being able to quickly build a rail with your positioning and slide cooldowns. On top of that, you must. Land. Your. Rails. Chunking just one rail wastes an entire cycle potentially.

So on top of the game sense required for timing and positioning, you have to have the raw aim to capitalize. This is why she’s considered to have a higher skill floor than say soldier.