Waiting for inspiration is awesome, but don't wait too long.
Daily tips.
There are several hacks to stop getting bored when writing long stories.
1. Create new characters (mostly new villains, small or big. Then as you go with the flow, decide whether they'd be evil for long or join sides with your main characters.) Works everytime for me!
2. Create a big conflict, watch your characters overcome them. Either cause a huge rumored to start flowing, or let a character get kidnapped? Have fun!
3. Take short breaks and work on other projects. Read other books, write a new story outline? Just try something else from your current book. Go for a walk? Experience nature. Many times I get ideas from random this!
Ever been stuck on chapter sixty something without knowing what to write next? How did you break through this phase? Let us know!