I think there is nothing more manly and more attractive than a nice, powerful and structured jawline. It's something that a lot of guys want. Unfortunately not everybody is blessed with perfect bone structure but everybody does have the opportunity to achieve that with just a couple tactics that you can do on your daily day-to-day life. So the most effective thing to have a more structured face shape and a powerful jawline that i have seen is body fat reduction. If you want to remove your baby fat cheeks and really show off the definition of your jawline and have your face more structured. The best thing you can do is reduce and cut down your body fat which will obviously remove any fat that you might have in your face. So this is achieved through proper exercise and really good nutrition. If you really want to achieve that you're gonna have to cut off your sodium intake daily. The more sodium you intake the more your body is going to retain water which is gonna make you look swollen.
Do not shave:
Your facial hair can be used to your advantage to structure your face so instead what you can do is shave down to a stubble, leave a little bit of hair(a shade), use a razor that has a precision blade. Draw up the line or shape up the line of your beard and you're gonna give your face that definition that you are looking for.
Jaw exercise:
Your jaw line is lined with muscles around the corner of those jaws with those muscles like any other muscles in your body. The more you work them out the more defined and stronger they are gonna look. So you can do simple exercises like chewing gum. A lot of people that recommend this say that you should chew gum constantly. Every time you cannot because it's not an akward exercise and you can do that on your free time all the time so be constantly chewing gum preferably sugar free gum to not cause any cavities but the more gum you chew you'll notice that your jaws are getting tight. Another easy exercise you can do is smile more smiling has a long lists of benefits to the muscles of your face. The more you work these out the stronger and tighter they are gonna look. So that's an easy thing to do just smile more. There are more exercises that you can find.
Your hair:
You can use things around to create the illusion of a stronger jaw and more defined face feature. For example your hair is very important. You have to pick up the hair cut that's modern and that's very tight on the side. What this is gonna do is it'll create that lean shape of a face no matter if you have a round face, square face whatever is the shape of your face. So haircuts like a high cut, high top , skin fade, undercut. These are modern haircut that are gonna keep your side tight and make your face look longer and leaner. You're gonna want to shy away from more classic haircuts that have fuller sides because this is gonna round off your face.
Take care of your skin:
Have a proper daily skin routine because you want you skin to be firm and tight. You don't want anything sagging or bloated or anything like that because that's gonna hide the definition of your jaw line. So another important aspect is to pick up products that encourage collagen production. Collagen is an active ingredient in your skin that help keep your skin nice firm and tight so pick a product that help your skin produce it.
I hope that this will help with your jawline journey.