Okay, given what little you've shared, and that you're on a vegetarian diet, here are some conscious, easy suggestions:
1. Swap some seed oils for avocado oil, almond oil, coconut oil, olive oil, extra virgin olive oil.
2. Eat almonds regularly for a snack.
3. Go through your pantry and toss out any processed, refined snacks where sugar or its many other names (corn syrup, fructose, glucose, etc.) appears as one of the first five listed in Ingredients on the label.
4. I'm assuming you don't have fruit juices, dried fruits, sweetened energy beverages or pop. If you do, cut back by at least half.
5. Go search on the web for "foods to raise HDL cholesterol." If much of your diet already consists of these foods, find a doctor who knows his business and who will give you a full lipid value panel and is open to discussing irregularities and next steps.