I think when we compare ourselves to others (in magazines, out and about etc.) it is always problematic for us. I know people say we need to find our own beauty within ourselves and I believe that to be true. It is also said that you cannot truly love another until you first love yourself. I certainly know that to be true. As I read so many posts on these forums (and have written several myself), I can see that we ALL struggle by focusing on our weaknesses…those WE know about ourselves and those that others have repeatedly pointed out to us in our pasts. But I think I see MUCH HOPE in your post. Because you have a DESIRE to see yourself as beautiful. That, to me, is SUCH a good sign. Because I honestly believe, on some level, then, that you KNOW there is beauty inside you! (and I can see it in you, too, from your post!)
Now, here's where the tricky part comes, in my opinion. Part of each of us wants to rebel against our current culture's definition of "beauty" (your mention of high heels etc. was a good example of that) and we want others to see the "beauty" in us without having to resort to changing our style of dress, hygiene habits etc. But sometimes we just don't "feel" beautiful for many reasons and so we become angry and jealous of those that are "perceived" to be beautiful in society. And I think that is a vicious, endless cycle if we stay there.
So, maybe you could try any or all of the following to help you see more beauty… (I know these have ALL helped me)
1. write down a list of GREAT things about yourself…things you do, who you are, anything you do to help others etc.

2. write down your BEST features…do you have beautiful eyes? Maybe the color of your hair? Maybe you have amazingly beautiful fingers? I LOVE how you said you were looking in the mirror. I think that is a GREAT idea. NOW, give yourself permission to LOVE at least ONE of your features and celebrate THAT as a part of your beauty.

3. Look at your current wardrobe. What are your favorite articles of clothing and why are they your favorites? (no wrong answers there, just whatever you're feeling) Do you own ANY article of clothing that you just feel amazing in? If the answer is "no" (and that's totally okay), then start an ADVENTURE…and start "hunting" for something that just makes you feel great. Then do not SHOP and BUY until you find that ONE THING (P.S. it could be a pair of socks or a blouse made of soft fabric or even a pair of shoes). It DOES NOT have to be something drastically different from your current wardrobe, but it CAN be if you want it to. The choice is up to you.

4. Write down a list of any of the things you want to change about yourself that you feel might be getting in the way of you seeing yourself as beautiful (do this ONLY once). Then separate the list into 3 categories: #1: Things I can change that I want to work to change #2. Things I can change but cannot currently change #3. Things I cannot change and have to let go. Then: Look at List #1 and pick ONE THING you want to work on and make a plan to do it. Hang up List #1 on your fridge or something and then gradually work on each one that you can change. Put List #2 in a drawer or somewhere out of sight where you can revisit it ONLY after you have worked on everything that you desire to work on from List #1. Finally, take list #3 and LIGHT IT ON FIRE (unless you're a pyromaniac, of course and then just rip it to shreds!)

5. Keep a journal of BEAUTIFUL things you see in nature around you (a sunrise, finding a beautiful shell, a garden blooming etc). Re-read and enjoy these moments and the beauty they bring to you and CONNECT yourself to those moments by saying things like "I am beautiful like a sunrise, because I start new every morning and today I am going to look for at least one beautiful thing about myself that I can celebrate!" Speaking positively over yourself ("I am beautiful because) rather than what we usually do "I don't feel beautiful because…" will have a HUGE impact if you will do it (and also believe it).

6. Take a picture of yourself once a month (or once a week or whatever you are comfortable with) and with each picture, write an accompanying message to yourself reminding yourself of what "beautiful" thing about yourself you are focusing on.

Then, look back on whatever you have been able to do (even if only ONE of the suggestions above) in a few weeks or months and hopefully you will be able to SEE more of the beauty that clearly exists in you. NOT compared to ANYONE ELSE but YOU!!!

Best of luck to you in this journey, beautiful dear!!!