The thought of being happy and smiling everyday is too idealistic. Face reality. You can be happy a lot, but you can’t deny that there are always obstacles or negative possibilities along the path of life that may make you want to frown or worry.
However, there is such a thing as being able to be happy and smile often. And it is also possible to make that an everyday goal; it’s good to stay positive. I was just pointing out certain things in my first paragraph just so you wouldn’t get your hopes up too high and find them crashing down later if something unfortunate may happen someday in the future.
But yes, it’s nice that you want to think positively. There are some people out there who absolutely refuse to think that way and it’s a saddening thought, so it’s nice to have people like you around who want these things. A way to be happy everyday is to find something to look forward to everyday whether it may be something like meeting friends, learning something new, doing something fun, etc. Or set some sort of goal for yourself each day, a goal that you can or will try to reach that will make your day.
As for worrying, it will be very difficult not to worry at all. There is likely to be some things in life that will worry you. That is something that you cannot escape from. But there is a way to lessen the stress of worrying if you are the type who happens to worry often. Learn how to be calm by opening your mind to many possibilities in life including the negativities, that way, nothing will be hiding from you (common-sense wise), and so you won’t need to hide from it either. Open your mind to the negativities in life. Open your mind to the positivities in life. Keep a balance the best that you can, and even if you may think you are not good at it, you will learn with practice and time. Learn how to be patient, learn how to be forgiving and kind (to others, and especially to yourself), and learn how to relax in any situation. Doing these things will bring out a sort of confidence within yourself, a kind of calm confidence that will lessen your worries, because even if you do end up worrying, you most likely won’t panic or feel paranoid, because you’ll know how to deal with it.
Doing all of what I just wrote above will also help you think positively. Less worrying = more positivity. And as I often say as my own motto, “Positivity conquers.” If you learn how to become a more optimistic person than a pessimistic one, then you’re bound to think more positively on a daily basis. However, that doesn’t mean that you should stop any pessimistic thoughts altogether. Being pessimistic is also good, so is being optimistic, but you want to try to keep a balance in between the two so that you won’t be driven too far to the point where it may eventually disappoint you. The best way I’d say to thinking positively is to be aware of the negative and the positive things, and that things can always turn out for the better if the effort for it is given. Believe in that, and see the good potential in all things whether we’re talking about people or a situation.
I hope this will help you to SMILE and be HAPPY everyday. Life is too short for regrets. 
