So you may ask, what's the best way to write out the date and time of the event?
Only the most informal invitations can get away with something like "on the 25th of July" but even then, if there's space to spell it out, "on the twenty-fifth of July.." is always the better option! On more formal invitations, there's absolutely no question- spell the date out.
The year is "two thousand and fifteen." Don't forget the "and."
The time of event(s) should also be written out: at five o'clock or at half after five o'clock, and not half past as so many of us do, by default.
"In the evening" isn't necessary (who's going to get married at five a.m.), but a lot of people like including it. Perhaps it's because we don't use the word "evening" enough. It is a lovely word.
If your event DOES commence in the morning hours, I would include "in the morning" so that people don't miss it
Hope that helps!
And as a bonus, "Please RSVP" is incorrect, since R.S.V.P. (or R.s.v.p.) stands for répondez s'il vous plaît, French for "please respond."