1) If you haven't already, eliminate the sodas (ALL sodas, diet included) and start drinking (unflavored) water.
2) Shift diet to primarily protein (I have seen some have really good success going exclusively to protein using the carnivore diet, but depending on who you ask, that is/is not an extreme move). Anything supplementary, ensure that it is minimally processed food. Google nutrient dense foods for ideas.
3) Get your 7-8 hours of consistent sleep
4) Walk