In my personal opinio have a cler list for grocery shopping is must that everyone would must to have...it is important as meal weekly planning...
First of all after you decide what you're going to eat for the entire week, open your kitchen cabinets and put in the list only things that you need to buy because they're not already into your cabinets...FOLLOW STRICTLY THE LIST YOU'VE WROTE!
If you are living alone with meal planning you don't fall into grocery store traps overbuying and then you need to put lot of food into trash bin...if you are a couple/family is fun and interesting decide menu all together
Before to hang out from your home, look into web if you can find some coupns to use to reduce your grocery's bill-they're great and useful used on things you buy and use but please don't became extreme couponer or the risk is to overspend on it-
What is better to buy in bulk? Well in my personal opinion some things that are essential and no perishables items in a home like: shampoos, toothpaste, pasta, crackers, toilet and kitchen papers...I mmust to be honest this will help you because you will have always at least one of this items into your cabinet..ergo you don't need to go another time into grocery and resist to temptations
Veggies: well I tend to eat seasonal and local,, this is helty and savvy...if in your city there is GAS support do subscription you'll receive veggie and fruit directly in front of your door and you'll discover new and delicious receipes about unknow veggie:P I tend to buy veggies once per week in a veggie and fruit shop near home...
JUNK FOOD: hei I'm not saying that you must to stay away from Mcdonald's & co for your entire life, but as I wrote I am trying to eat more healtier is possible but I'm human and I offer junk food once per month.. considering it part of reward to give to myself!!!
this pic shows the pyramid of food we'd must to follow