1.) Don't book any venue without seeing it. My only exception to this is if you have a wedding planner working your behalf and doing the scouting for you.
2.) Don't work with any vendor without a contract. Contracts put everyone’s expectations and obligations on paper. And you never want to pay any vendors full amount after your consultation even if you love his/her work.
3.) Don't start planning or interviewing vendors without a budget. You will waste your time and the time of the vendors you meet.
4.) Don't be afraid to speak up with your vendors. If you have questions or concerns, ask while changes can still be made as opposed to being stuck with something you will regret on your wedding day.
5.) Don't take your family and friends for granted. I've wrote about this topic previously, but your bridesmaids and groomsmen will spend a small fortune to participate in your day. Please treat them nicely.
6.) Don't forget what you are planning for— you're getting married to the man of your dreams and to his family. This is your motivation and the reason why you're planning. (click here to read more)
7.) Don't pick a vendor if you feel uncomfortable & somewhat shady :) Do trust your instinct!
8.) Don't choose a photographer with your budget solely in mind. This is the only thing that will preserve your memories for your special day. Please choose someone with style, talent and charisma, not because she/he fits your budget.
9.) Don't go to your catering tasting starving. Everything will taste good. But do remember that food tasting will always taste better than the actual day of your wedding.