Taking in the waist of jeans is a common alteration that can be done to make jeans fit more snugly. This can be done by hand or by machine, and there are a few different methods that can be used. One method is to simply take in the side seams of the jeans. This will reduce the overall width of the waist, but it will also make the jeans shorter. Another method is to take in the back waistband of the jeans. This will reduce the width of the waist without making the jeans shorter. Finally, it is also possible to take in the front waistband of the jeans. This will reduce the width of the waist and also make the jeans sit higher on the waist.
Taking in the waist of jeans can be a relatively simple alteration, but it is important to take your time and do it carefully. If you are not sure how to do it yourself, you can always take your jeans to a tailor or seamstress to have it done professionally.