In order to take in pants at the waistband, belt loops fight back, podposite belt and cut it in half. At the seam, remove the part of the stitch (finishing).

Further work with secondary suture must be cut so that the pants better fit.
Next, stitch the belt, put it on the pants, and restore the finishing line.

Then re-sew the belt loops. After that, the pants will sit much better.
In order to take in pants at the seams, put on your pants, stand in front of a mirror and mark the places where you need to reduce the volume: side seams, back center seam and seams on the inner part of the leg.

Also check other places that you have to cut.
Take off your trousers and keen, first one pant leg along the planned lines.

Standing in front of a mirror and compare both legs, if you are satisfied, remove, asprivate seams and sew along the planned lines.
Remember to model the pants preserved, you need to subtract equally with both external and internal sides of the pants.
After I make the new seams, athlete them and try on the pants.
Only after make sure that you are satisfied, cut the excess seam and again sewn.
As you can see, there is nothing complicated about the closure of the pants as the waistband and side seams. With diligence and diligence, you'll be able to wear your favorite pants.