I have made tuna salad and put it in an ice cream cone. My kids love that. I make up biscuit pizzas and let my 3 year old put whatever she wants on them. I make up my own "lunchables" with ritz crackers, cheese and deli meats. My kids also like the frozen burritos, chicken nuggets, fish sticks, taquitos...easy stuff to just put in the microwave or oven. I also get tortilla shells and put peanut butter on them and roll them up with bananas, or even use the shells and spread cream cheese on it and roll it up with lunch meat.
If your kids like jello, you can try to put some fruit in jellow. Celery and peanut butter is good. Have you tried trail mix and add dried fruit in it? For my kids I have never had a problem with them eating veggies (they always choose the veggies and fruit over the meats anyways). But with other kids I watch, they must eat at least 2 bites of whatever veggies or fruits I put in front of them. For toddlers they seem to go through spells and like something one day and not the other, so sometimes I find that after the 2 required bites they will eat it up because they actually do like it.
What has worked for me when I was cutting out soda, I would drink twice as much water as soda. So if I had a 20 ounce soda, I would have to drink 40 ounces of water before drinking another soda. And then I just cut down on the soda size until I didn't need any more. When I was going to camp when I was younger, the counselors made us drink water in between whatever non-water drink we had. So at meals, if we had a glass of milk, then water, then we could have whatever (juice, lemonade) and then water...and I have carried that over now with my kids and with me. That way I know I am getting enough water a day and not really have to worry about too much koolaid or suggary juices and not enough water intake.