May i know which is right?

May i know which is right? Do people always say "it is important to you, " instead of saying " it is important for you" ? But as for the sentence," gardening is hard for me ," or " gardening is hard to me ," or " it is hard for me to garden. " Which is common? I mean "when" people will use "to " and "when " they will use"for." Do they often say " it is important for me to finish in time," instead of " it is important to me to finish in time." ?