Quick wins on the diet-improvement front: less junk (booze, crisps, fast food/takeaway), more fruit & veggies, especially green veggies. If you live anywhere near a green space with wild patches then head down there with an empty container of some sort for free tasty fruit - it's blackberrying season
Nuts are actually pretty good, although if you're eating the salted/roasted/etc sort that come in snack-type packets, rather less so. Raw nuts (almonds, peanuts, cashews, whatever) are a good source of protein & good fats.