Cover all your wedding planning bases with these expert tips no to-be-wed should be without.

When planning your wedding, there are things that are nice to know, and there are things you need to know—advice so essential any bride who's lucky enough to hear it thinks, "I'm so glad someone told me that!" If you're wondering whether there's something you may have missed (or even if you've got everything under control), check out our indispensable planning secrets below.

1. Guests Come First

Get a grip on the approximate number of guests you'll invite before settling on a venue. This will ensure there's ample space for your crew. As a rule of thumb, allow for 25 to 30 square feet per guest. That may seem like a lot, but it's really not if you count the space you'll need for the tables, bustling waiters, the band and a dance floor.

2. Investigate Wedding Blackout Dates

Know ahead of time if your wedding date falls on the same day as a trade conference, charity walk or other local event that could affect traffic and hotel room availability. Here's a handy list of potentially problematic wedding dates coming up in the calendar.