Married in 24 days! Advice?

✩M
I'm marrying my best friend in 24 days and while I'm very excited, I'm also a little nervous. We've been together for almost 4 years so I don't imagine our relationship will differ too much from the way it is now, but I'm just curious what changes you all went through when you got married? Any advice on having a happy marriage or even just advice for the wedding day itself would be much appreciated :3