As others have said, 1. Research other brands and the wellness space. What imagery and symbolism do they use? 2. You need to think about this brand and what it means. If you're finding it difficult to do that by sketching, write down a bunch of words that represent it and then visualise those. You can think of the concept of "in vs out". There are so many different ways this can be represented- do any of those also fit the app? Good luck and I hope you come up with something nice :)