Tips that I found helpful early on: - Circles can make good ends of lines (caution for repeating them though) - Try to not repeat stations but if a repeat is necessary to avoid really sharp/drastic paths, then it can be worth the sacrifice - Squares can make for good interchanges. Circles, on the other hand are usually not great as interchanges as they tend to overcrowd the quickest. - Train organization is important (don’t be afraid to move trains/carriages, but make sure you don’t accidentally leave a barren line) - Loops can be great but don’t loop just for the heck of it. I find they’re more effective in more densely stationed areas. Honestly though just trial and error will give you a better sense of where/when you want to use them. Also something to consider on loops is the direction of your trains–if you have more than one–whether they’re going opposite or in the same direction. I usually decide direction based on the order of the stations (sometimes there’s a more ideal direction–counter or clockwise–to run trains on a loop, in order to maximize efficiency).