Weight Loss Tips?

Cait
I'm a very short person that's very chubby and I hate it. I date a really tall guy who's a twig. I feel huge compared to him. I've been wanting to lose weight but it's really pushing me now that I'm comparing myself to him. 
I've started eating a lot healthier since the new year and I lose weight pretty fast. I know I've lost weight within the last two weeks and it amazes me. 
I'm currently an XL in tops and it's my goal to be a Medium by the time prom comes around. I've done it before so I know I can do it. It's just a matter of keeping the weight off. 
Does anyone have any tips to make sure I can keep the weight off?
Note: I do f have access to going to any kind of gym and I walk about a mile home from school up hill every day. 
I also track my calories every day and I try not to go over 1,580 a day and it's been working pretty well for the past few weeks. 
If anyone has any helpful tips for a chubby girl like me, I could use it