If I have one piece of advice to give you all about what to search for in your quest for What Next, it's to find where the line blurs between hard work and happiness for you. To find that thing where working hard at it makes you happy, and where you're happy to work hard at it.
I've never had a moment when I thought: "Tom, you've made it!", and I don't think I want to, because that feels like you've reached the end; that you've crossed the finish line. But to me there is no end. An achievement is not a finish line; it's a checkpoint on a far greater journey. It's a moment to pause, to take a breath and look back and enjoy what you've experienced and be grateful for it, but then to turn around and look towards the next checkpoint, the next achievement.
Do not let the day end without you asking yourself one great question. So many things do question our thoughts. Questions of all forms and from all spheres of life do bother us. Sometimes, questions are the best answers to questions. When you ponder over a question, ask another question which will questing the question. Mostly, the best answers to questions are the best questions. Questions that questing the questions rightly give the right answers. Remember, never a day without a great question!