The most reliable way to tighten sagging skin without surgery is by using injectable fillers like Juvederm, Restylane, Radiesse, etc. This is a little like inflating a beach ball to address the pockets and bulges. For example, by using a filler to restore volume to the cheeks, you can lessen the appearance of the jowls to some extent.
Another appraoch involves injecting filler into the area just in front of the jowls (call the pre-jowl sulcus) which can reduce the appearance of the jowl. Fat transfer can achieve similar results, but you might consider this approach surgery, even though the incisions are insignificant.
There are a number of radiofrequency devices that claim to be able to "tighten" skin without surgery. Certainly, some patients seem to have gotten good results, but it appears that this is seen in a minority of patients You can spend a good amount of money on these kinds of treatments and see very little (if any) results.
