i find it best to set little challenges, especially before you go out for a ride, i found that to work great for me makes me know when i am actually having a good days riding. This only works for things that u know the actaul size of, like say u wanna do this gap or tap today, and a few other things depending on the location u are going to, and try and do them. Obviously set them within your limit. Not only do i push myself to meet the target, i find that I am not thinking about what i could do next or whether its interesting or if i am bored. i am just focused on trying what i came to try, and before i know it 2 hours have gone by. And this is riding alone btw, its even better if ur our on a group ride. be interested to know it works out for u, i know it would take a bit of discipline and certainly a different mentality, but thats what trials is about, being serious about it would definitely make u enjoy it more pure because u know ur progressing.