I believe that technology will be our biggest downfall when it comes to structural issues. We already see it with kids that are getting on phones and iPads at such a young age. The forehead posture (head slopping down forward) is becoming very common with kids as well as the older population.
Beside spending less time looking down on the phone, what else can be done? First thing: strengthen those very muscles that are lacking strength. The neck and upper back are the usual suspects.
Usually, we see a strength discrepancy between right and left scapular complex, mostly trapezius and rotator cuffs. Unilateral work is a must in this case.
One of my go to exercise is the row to neck. Grab a single handle and attach it to a seated row pulley. Pull with one hand keeping your elbow high and in line with your shoulder as if you are trying to pull the handle to your neck.
One of the most common mistakes I see is people leaning too far back. Keep your upper body as perpendicular to the floor as possible and with your chest out, never with a rounded back.