Wishing well has three meanings. By tossing a coin into a wishing well, I wish wellness for you, and my wish was well formulated; I wished well. In seeking wellbeing all three meanings can be useful.
A wishing well is a good metaphor for our subconscious. Imagine the kind of well you encounter in a fairy tail. A circular stone base with a triangular roof and a bucket hanging from a shaft. Imagine the deep pit leading to unseen water, which will receive a coin and give back a faint echoey splash. That is good imagery to use as you wish wellness for yourself or others.
To wish yourself well, wish well by considering your wish well. Imagine what wellness looks like. Think about the wellness you currently have. Think about what needs to change to make you well. Think about your behavior and your thoughts. Think about your relationships. Think about your desires. Imagine how these things will be when you are well. Imagine how you will feel when you are well.
When you have formulated your wish, take the image of wellness that you have created and forge a coin with it. Then make your wish. Throw the coin into the ancient well and listen for the splash. If the well is too deep, or the coin to small, there will only be silence. Your wish will be planted deep in your mind. If you have wished well, your mind and the universe will work to attract wellness into your life.
If this seems like too much effort, you can make your wish before blowing out your birthday candles. That could work too. I wish you well.