How can you make a sweater vest tighter?

To make a sweater vest tighter, you can try a few methods. First, consider sewing darts or taking in the side seams if you're comfortable with sewing. Alternatively, you can shrink the sweater vest by washing it in hot water and drying it on high heat, but test a small area first to avoid over-shrinking. Lastly, using safety pins or fashion tape can provide a temporary fix by gathering excess fabric.