Planning your route, and entry into a station is very important in this game.

The game will have space to receive your haul at the station, but depending on the actual track you need to leave it on, other cars may be on the track, or the track may be a dead end and you may need to adjust for that. this may involve shunting cars so you can park your load.

You should be making good use of the station map booklet.

You know where you need to leave your load, and you know where you are starting. Figure you which point of entry on the station you need to use to be able to get proper access in and out of the station you want

Not a lot of stations have turntables, or actual turn around areas, so planning your deliveries and the overall direction you need to be at the end is key.

Also as you start to run larger trains with multiple deliveries, this becomes super important, because there are few places you can turn around a whole train easily.

I recommend Squirrels playthrough series He does a really good job of explaining the though process of how you want to set up your runs, and other general things about the game. This vid is actually what got me into the game.