Cut off the base so it sits flat on your cutting board, then slice straight down through the center where the stem is (or would be).  Use a spoon to scoop out the seeds and stringy bits from the middle, then slice each half into thinner pieces. You can start with wedges and break those down smaller, or you can simply slice each half like you would a melon. Don’t forget to remove the outer peel as well. And if your pumpkin is on the larger size, you can cut each slice in half to make smaller pieces.