When I was working, I always tried to take my lunch, drinks, snacks.. whatever.
Frist tip, make sure you have lots of little containers to take your lunch in, all sizes and shapes. Lots of Ziplocs, foil and cling wrap( if you can use it.. its outlawed at my house!!) Also some utensils' and keep paper plates on hand to use to put your lunch on. I use to put pretty napkins that I had left over from some holiday or party or that I picked up somewhere in my lunch bag it made lunch seem a bit brighter. Pick up those picnic salt and pepper shaker to keep in your bag.
Planning out what you are going to have helps a lot to, go by what's seasonal and on sale.
I had a drawer that I kept - crackers at least 2 boxes, raisins/cranberries, a jar of peanut butter, breakfast / granola bars, something sweet and a couple of cans of soup, this was for when I did not have time or feel like putting together lunch. Drinks - a 12 pack of Coke, capri suns or some other juice pack and 6 pack of water under my desk.
Rotisserie chicken is good way to make a couple meals, chicken salad on a pita, with lettuce and tomato, chop into chunks to add in salads, add into some left over rice, or pasta.
Deli meat and Cheese roll ups / slice as pinwheels, you can use some soft spread flavored cream cheese in the middle, with a few crackers, lettuce and tomato salad, baby carrots, celery, apple slices.
Keep on hand, baby carrots, celery washed and chopped, grape tomatoes, bags of lettuce mix, a couple of different salad dressing, flour wraps, shredded cheese
Boiled eggs (a couple) ready to use for egg salad or to add into a chef salad or eat plain with some veggies and dip.
Check out the deli case's for some single serving options, We shop at Publix, and in there seafood department, in the cold case below there is always some type of seafood salad, or pasta seafood salad, sushi, and some single serve soups that are really good.
In the frozen food aisle - egg rolls, cheese sticks, flavored chicken wings, lots of options here.
Lloyds BBQ is really good - BBQ sandwiches, you can put on top of chips for a BBQ nacho type thing
On taco night make a larger than normally batch, and use for taco salad, nachos.