First off, take my advice as it applies to you and discard it where it doesn't. I'm speaking from my own experience, and it's possible nothing I say applies to you.
So, my husband and I are pretty skint at the moment, so we're slowly becoming masters of eating healthy on the cheap. We currently spend about $60/week on groceries (no couponing), and we feel we eat rather well. (Also, at this point we have a large stockpile of meat and veggies in the freezer. If we got snowed in for a couple weeks tomorrow, we would not go hungry. This also includes cleaning products, personal hygiene products, etc.) First, you have to figure out what you like and what you don't. If you're anything like me, trying to eat "healthy" things that don't satisfy you leads to eating absolutely everything else.
We buy a lot of frozen vegetables. (I am assuming you're in the US? Circulars are a good way to find out when sales are happening.) If you plan well, you can get a bag for a dollar. Filling half the plate with steamed vegetables is a good way to cut calories and costs.
You should also try taking advantage of the power of perception. Use a smaller plate. Not a tiny one, but smaller. You'll be able to fill the plate (half with veggies) and feel like you're having a full meal while eating less. Trying to eat less on a large plate will make you feel like you're missing out.
Make spice blends. Eating a lot of chicken or steak or <insert meat> can get boring, and you might be tempted to substitute pasta or something else that just isn't good for you out of boredom. If you can vary the taste significantly, you won't be as tempted. The past two nights we had a cheap cut of steak (buy one get one). The first night, we had a chinese-style meal. Last night, we went with TexMex. It didn't feel anything like having the same meal two nights in a row. If I'm honest with myself, it really was the same meal, but it didn't feel like it.
Consider weighing everything at first. I've got a kitchen scale, and I learned pretty quickly that my perception of a serving size was NOT accurate. You might think
you're having a serving of something healthy, but you might actually be having an awful lot of something which, while healthy in moderation, is a pile of calories in the portions you're having. My idea of a serving was frequently 2.5 servings.
Consider soups. Something with a water/stock base will be filling without loading too much on the calories.
When you think you're hungry, try drinking a glass of water and then waiting ten minutes. I find that what I think of as ravenous hunger is frequently dehydration. How I wish I'd figured that one out when I was still a teenager!
Have you considered using a calorie counter like MyFitnessPal or LoseIt? Try just recording everything you eat for a day (preferably while using a kitchen scale). Get an idea of where you're taking major calorie hits and figure out if you can forgo or decrease those items in your diet.
Eat small, regular meals. Allowing yourself to get really hungry will probably lead to full abandon when meal times come around.
Don't start out with your calories too low. If you do and you're anything like me, you'll give up. Being hungry all the time isn't fun.
And finally, forgive yourself. Forgive yourself for letting it get where it has. Forgive yourself when you go over calories or have a mess up day. Every day is a chance to start again. Heck, every meal is a chance to start again. If you give up every time you make a mistake, you'll never make progress, because not one of us here is perfect.