Hi TR and welcome to the guild. I work with many people from the Philippines every day as my company has a significant call center presence there.
Your map is quite fascinating already, and you've already done the hard part. What I want to suggest to you now may seem counter-intuitive, but I think you should go through a few tutorials using Photoshop... Ascension has a fantastic one out there. This will help open you mind to new ideas and teach you how to do things you may not know how to do. Once you have done some of this, I think that ideas for ways to improve your existing map with start to flow quickly.
One other thing I'd like to recommend. You should definitely spend some quality time with the lasso and pull some of the elements into different layers. Forests should have their own, as should mountains, etc. You will be very glad you did.
I think you'll find that most people here are resistant to telling you what to do. We want you to understand more of what you can do and then experience the joy of deciding yourself what works best. Good luck and I look forward to seeing what you do with your lovely map.