it depends how you want to approach it, you either select the other vertices (multiselection)(and it's hard to explain just by the picture, as you have a smoothing modifier overlayed) or there are "soft selection" options as well. It's more a question of trial and error until you, in your mind, know how to get the results you would like to achieve.
There are several approaches. The easiest but most tideous way is to move each vertice separately, i would suggest, save your file and then just play with different attempts, you'll soon find what's best to do in that particular situation
I would assume it's Blender? It might not be directly related, but here is a high poly speedbuild of mine, you can probably find some answers to perfect your workflow.
(different program, same workflow basically)