Consider how your decisions will impact your guests — eg your choice of venue; will it involve guests tramping through fields to get to portaloos? Will there be sufficient accommodation available? Be considerate.
Develop a good relationship with the hotel/venue team — it all comes down to them on the day to execute your plan.
Remember this is a marriage, the start of your life together and not just a wedding. It’s just one day. If you enjoy it as a couple, your guests will enjoy it.
Food and photos. People will remember good food and you’ll have the photos for years to come.
Decorating the venue — unless you’ve the time, energy and budget leave it to the hotel who will do a great job.
Latest trend: Donut walls (exactly as the name suggests) and high end food and drink stations and food carts instead of BBQs: “It’s about serving food and drink in creative, instagrammable ways.”