I was fired up to give you some suggestions, then I noticed that you're vegan
Can't really help you at all with diet tips except to make sure you are eating enough proteins and dark leafy greens for calcium.
Make sure that you focus on drinking bunches of water every day as much as you focus on your food intake.
Eating 5 or 6 small meals a day will increase your metabolism. (Snack between breakfast and lunch, and lunch and supper. If early enough, snack after supper)
Resistance training will build lean muscle which are the calorie burning machines in our bodies.
There's my tips! But hey, you're only 18. Youth on your side makes it a little easier for you to shed the pounds. You can do it!