When you create a blend wherein the primary reason of creation is its aroma. While using such a blend therapeutic gain may also happen. But the sole reason of creation of a blend is its aroma. So you can experiment and try making different blends using your creativity. You may not get the kind of aroma you are looking for in one go but trial and error is the way to go. Usually essential oils from the same category go well. So try and pick oils for a blend preferably from the same category. After getting the scent you are satisfied with, mix it in carrier oils and store in a bottle.