I think people have hit the nail on the head, that the same old same old gets boring and the key to keeping interested I think comes down to change. Okay, but what does that mean? It could mean you feel like you want to do more of an operations focused layout. Does that mean changing the layout, redoing the track, make it more 'operations oriented'? It can, but it is also about imagination. For example, you have a layout that has sidings and accessories. So for example, let's say you have a coal loader. Well, does anyone on the layout need coal? Or could you set it up where a hopper is loaded with coal, and then it is taken to another siding on the layout, where presumably it is picked up by a 'connecting' train line (want to model that cheaply? Set up some track, not near the siding, and put a static engine representing another line (you can buy a dummy or 'junk' engine at a train show cheaply to represent that). That could be used as a destination for a lot of things.
You can also re-arrange where industries on the layout are located. Placing them apart from each other (or as someone else suggested, a scenic divider).
Obviously, things like detailing the layout can help, add details to scenes. If you have a coal loader, have details around it, a small office, signs, etc. If you like the idea of the transfer point to another railroad (with the dummy track I mentioned), have details around that, a common loading dock, forklifts, cranes, that suggest activity.
Or you might want to redo the layout, do a different track plan, and incorporate a new theme (the only difference between scale and postwar/tinplate/toy train is in the depiction of the trains, not in what they can do). That doesn't mean you need to build a point to point switching layout, you can incorporate 'loop running' into it (for example, that train going around the loop for 15 or 20 minutes, until it gets to its destination, represents a long run), while that is going on, you could be putting a coal car under the coal loader, be picking up a load of milk or cattle or wood at the various types of accessories. Accessories themselves are interesting, you can try and fit them in better with the scenery, make them more hi rail, to make them look more like a functioning piece of equipment then a 'toy' to be played with.
You could also if desired change the layout over to hi rail, maybe switch track to something more realistic (and obviously your own desire and yes, finances play role in that, too). If you like tinplate track you can still make that look better by ballasting it and adding ties, that can make it more fun to imagine running a railroad. We all change with time, what we like changes and the nice part is there are always options. I agree with others that reading and watching videos on you tube might help, to get ideas from others. Maybe you will decide you want more realism, or want to go whole hog and find a way in the space you have to make a truly operations oriented layout. Seeing what others have done for me (besides being jealous, of course, looking at one of these intricate layouts, but then realizing how slowly I am building a modest 9x14 layout, not even halfway through track laying, a 20x40 would take me like 900 years at my present pace) gives me an idea of what I would like to do or not do as I go forward.