So you want a smaller waistline?
First, we need to realize that genetics play a huge role in it. We all have a different body composition based on our genetics. Some are more lucky than others. Some have narrow waste and others wide shoulders. You get what you get. However, even for those of us who are not that lucky, it is possible to look better. Besides our genetics, the biggest contributor is fat between your muscles and skin (subcutaneous fat) as well as fat around your internal organs (visceral fat).
Tense up your core muscles and try to pinch your sides. If you can grab more than one centimetre of tissue, you got some fat under your skin. If it is hard to grab more than that, but you feel bloated and your belly is sticking out, you may have too much fat around your internal organs. If you want a smaller waistline, you will have to get rid of both. Keep it simple, fat loss is fat loss. Do not fall for the greatest new waist belt device or belly slimming drink that destroys visceral fat forever. Those are only great for people who sell them.
You need to get on a fat loss nutrition plan and start an exercise program designed for fat loss (not a program for bodybuilding or athletic performance). There are many fat loss diets out there. Some work better than others and some don’t work at all. Find the one that works for you and stick to it. I recommend plans that address lowering insulin levels in the first place, and second, avoiding high calorie density foods. The nutrition plan that promotes both, is the one that works the best. Once you have the right diet, you can slightly change your body composition by targeting different parts of the body. Do your core exercises with high reps and speed in order to keep your muscles smaller and leaner. Do not go crazy with obliques.
You can also do weighted exercises for your glutes and thighs to build some size. Visually, your waist will look smaller when you increase the size of your hips and glutes a bit. Always keep in mind though, you can’t out-train your diet!