I am in the process of setting up my own business and have a meeting with a venue this week. Its my first official meeting as a 'planner' so i am very nervous!
Just be yourself when you meet the supplier. They will appreciate it more if you are honest and down to earth. They don't want someone coming into their place of business and bossing them around, so you need to build a repore with them so that they will listen to you when you have to give orders but still feel like they are in control of their own work. There is no need to put on a act just be yourself and have fun, the more friends you make the better your business will be.