Board Thread:Questions and Answers/@comment-29814969-20160831081612/@comment-27701762-20160831141818

The time between encounters gets longer and longer as you kill more enemies, making grinding tougher. This is especially true if you're just walking around the same room, as the number of steps required to find the next encounter grows with each encounter.

My advice would be the following:

1) Find a room where you know that there are encounters. This could be one of the room with the rocks and spikes, the room after Toriel leaves you alone, one of the rooms with the red/green/blue switches, etc.

2) Hold UP+DOWN, pressing no other buttons. This will cause you to do a wallhump, which makes the step counter go by a bit more quickly. Keep holding it until you get an encounter. It could take several minutes.