The doctor didn't give you any guidelines? Well, there are different schools of thought on this. There is strict low fat/high carb diets, there are low carb diets, there is 'clean' eating, etc.
What type of eating style do you have now? If you consume a lot of sugars, cutting those back will help reduce triglycerides. Eating healthy fats will help increase HDL (the good kind).
This is a blog by a cardiologist, he has a lot of interesting information about cholesterol, statins, etc. I gather from reading his posts that he prefers diet over drugs for his patients. heartscanblog.blogspot.com/