I usually have trouble with my self-esteem and it is definitely something that I need to work on. I am mostly insecure about my looks which is hard because that is not really something that you can change unless you get plastic surgery. How can I learn to just like myself for the way that I look?
Ok, here's the thing about looks. As you've stated, there are things you can change. You can lose weight and get fit. You can buy close that flatter your figure. You can get a nice hair cut. Outside of that, it's largely out of your control.
Some people will find you ugly. Some people will find you beautiful. Some people will find you average. Stop worrying about the ones in the category that finds you ugly...they don't matter.
There will always be someone hotter than you. Take Angelina Jolie. As beautiful as she is, and as hot as she is - let's even say she's the hottest woman on the planet...Ok, so she's the ONLY one that doesn't have someone better looking than her...and even then, some people think she's unattractive. See how subjective all of that is?
Well for me, I go to the gym. When I gain more muscle, or burn off the doritos I ate last week, I feel good about myself. I can see progress.
Try picking up a hobby, that you can feel good about. Ofcourse, if you have worries about your face, they won't go away. But you will stop caring when you have something to be happy and excited about :D
I think working out is a great start if you don't already work out regularly. Not necessarily because anything needs to change with your body, but the endorphins really contribute to confidence building. Plus, working out gives you that feeling that you're making a positive change toward your appearance, and it can alter your whole perspective. The blood flow really helps with skin and hair, too!
After that, I think it's about repetition to change the thoughts you always tell yourself. It's cheesy, but you need to make it a rule that you don't say anything negative to yourself about your looks. Start forcing yourself to say positive things until you start to believe them. Negative self-talk is so limiting.
Plus, it can't hurt to try out new makeup and hairstyles in the meantime and see if it gives a quick confidence boost!
Personally, I think that if you have a positive outlook on life in general, you'll also feel more positive and confident in your own skin. Whenever you look at yourself in the mirror, stop worrying about your flaws. Compliment yourself when you look in the mirror. Smile at yourself. Tell yourself "I really like my eyes" or "my hair looks good today". Keep doing that every day, and find different things to love about yourself each time. It can be something that isn't physical, either. Like, "I love how passionate I am in terms of ---" The happier you are on the inside, the happier you'll be with your outside. Your happiness will shine through and it will make you both look and feel a lot better. :)
Just try to accept that you are who you are. Do a rating on here if you want. (i read your comment about guys saying all girls are beautiful, but I also did a rating question once, and not everyone was that positive.) You say you're pretty insecure about your face -> rate your face only?