Best to cut your cake slightly cold/room temp.

A cutting board and long knife are extremely helpful.

For your 14+ servings hold the cutting board up right on the side of the cake and make your cut.

once you have reached the bottom of your cake you can then lay the cutting board down and cut the rest of your pieces from there.

If you want smaller/shorter pieces you can cut the cake in long strips and then down the center of the cake horizontally.