One of the hardest things to do with bento, especially if you're a picky eater, is find things that taste good and are relatively healthy. If you pack a sandwich everyday then your bento is not much more than a fancy brown bag lunch. I'm not saying that sandwiches are bad (I love my sandwiches) but bentos are your chance to mix it up and get some variety in your lunches.
An easy way to do this, especially for a child or picky eater, is to sit down and list as many foods you like as possible. However, there are some requirements. They have to be:
1. easy to obtain
2. fairly simple to make or have the ability to be made in bulk and frozen
3. able to fit and sit in a lunch for at least a couple hours at room temperature.
I adore melon-pan, but it's not everyday I can get down to the asian market. I would love to have some corned beef in my lunch but it's not exactly a quick food to make and doesn't freeze well after cooked. Ice cream is delicious, but it doesn't fare well out of the freezer for hours.
Don't be afraid to list foods that you're unsure if they will work or not. You can always make a small batch and put it in your lunch for a try. Or you can give it a shot on a weekend, when you don't have a bento day, and just leave it covered on the counter for a couple hours. If you don't like it just cross it off your list.
List prepared main meal-type dishes such as steamed salmon or roasted veggies. But also list easy finger fruits and veggies. If they aren't in season just list them anyway. Because when they are your list will remind you to pick them up. If you find something you like and think would work, just add it to your list and give it a try.
The purpose of the list is to give you something to look at while planning your lunch. The list will be there so you don't have to tap your pen against your lips and wonder "what foods do I like that would go with this?" you can just go down your list and pick the things you want in your lunch. The way to fast bento making is a lot of initial pre-planning, and the list is the first step.
So here are a couple things on my list, just to give you a glance:
Mini meatballs
Scrambled eggs (still untested)
Rice
Lucnchmeat & cheese rolls
Stuffed bread
Spinach
Tomatoes
Grapes
Orange
Kiwi
Teriyaki shrimp/steak/chicken
Wontons
This is only a small bit of my list and I add to it every week or so as I discover new things I like. Up there you can see I have food I prepare and freeze for later use (meatballs, teriyaki), food I can put together quickly while making my lunch (lunchmeat and cheese rolls), and easy finger food I can just throw into my bento and be done (grapes, tomatoes).
I also have items I can make ahead and will keep in the fridge for a couple days (stuffed bread) and items that can be prepared, frozen, then cooked quickly on the day of bento making (wontons). I even have things I haven't tried yet (scrambled eggs) that I'm unsure will work or not.
You can always have food that isn't on the list. Sometimes you have leftovers from the night before that will go well in a bento but wouldn't make the list originally. Or sometimes you just want a special treat and you have time the day or morning before to prepare it. Sushi isn't exactly easy to make, doesn't keep for more than a day really, and is virtually impossible to freeze. I still enjoy making it the night before sometimes to have it as a special treat in my lunch.
So if you're struggling to think of foods that will work well in your bento take some time to sit down and write out your list. It will save you a lot of planning and prepping time in the future.