I am undecided on which business idea I like most, between a Banquet Hall or a Day Spa. Which is a better business for starters and where do I begin.

It depends on where you live. I'd go with the Day Spa idea if you live in or near a big city where you will get plenty of clients. Banquet halls do draw crowds, everyone must eat. How about a Day Spa with a healthy restaurant in it?

I agree that owning a day spa might be the way to go, depending on where it would be located, because you might have a steadier income on a daily basis then if you ran a banquet hall business.

For information on starting a day spa, please see the following links.
How to Start a Spa Business - Open a Day Spa - How to Start a Day Spa
How to Open a Salon or Day Spa - Entrepreneur.com
How to Become a Spa Owner, Starting a Spa Business, Salon Spa, Home Spa, Spa Retreat
http://www.businessinfoguide.com/spa.htm
Business Opportunities Weblog | Start a Day Spa

Concerning opening a banquet hall, you might want to check out the links at the bottom of this page to questions about that and see what the answers have been. Questions about opening a banquet hall appear on this site fairly frequently.