Wow!
Well you're going to hear this only about 5 million times on your wedding day and honeymoon, but CONGRATS! Marriage is awesome.
I just got married last August, so I'm a newly-wed too.
18 days, it's getting down to the wire, I hope all the plans and stuff are all set, so all you have to worry about now is being beautiful on your big day! In the days before my wedding it felt like the day would never come....but it did, and it was wonderful. The Poconos were wonderful as well
I would suggest picking up the book His Needs, Her Needs, as well as His Needs, Her Needs for Parents, if you have kids. I have both those books, theyre wonderful. You can read them easily within the next 2 1/2 weeks if you really wanted. They make a simple outline on how to make your marriage affair-proof, as well as run much more peacefully in all areas.
Other than that, just ask other Christians couples, perhaps older and more wise couples, what they've done to make their marriage succeed. I bet they'd have some great things to share with you!
If I could give you one peice of advice, and only one, I would say, (besides stay close to God), be transparent with eachother! That means no lying/hiding/deceiving, anything like that. If you are honest in all things, you will be able to avoid problems before they even start. You will also grow to respect eachother at a whole new level. My husband is very transparent with me, he tells me things that I know other husbands wouldn't dare tell their wives. Sometimes what he tells me hurts, but I love knowing the truth, and in the end we're both much better off for it.
Good luck with everything!