When I was entering manuscript contests, I had many choices of places to enter since I thought my book was a romance and I was a member of Romance Writers of America which has many local chapters hosting contests. I also entered contests in my home state, my city and several others recommended by friends and my writing instructor, Bonnie Hearn Hill.
Do you know where to find contests? If not, you'll find there are many links to contests by doing an Internet search. However, you must be careful with some of these. The true benefits of entering contests is to get feedback that will help improve your writing. Other benefits are to make contact with publishers and agents. Study how the contest can help you. Some of the contests you find on the Internet are more interested in selling you something. There is often a fee for entering a contest to cover costs, but the cost should be minimal.
You'll be more successful going through organizations you know and the ones who are reputable. I mentioned Romance Writers of America. You may want to also look at American Christian Fiction Writers. ACFW has national and chapter contests, too. Not all the chapters shown below have contests, but most offer support for beginning writers. Most require membership in both national and chapter organizations to reap the benefits, however. Check these chapter websites for more information:
ACFW Great Lakes Chapter: http://greatlakeschapter.blogspot.com/
Indiana Chapter of ACFW: http://hoosierink.blogspot.com/
ACFW Ohio: http://www.acfwohio.com/
His Writers: Heavenly Inspired Story Writers: http://www.hiswriters.acfwcolorado.com/
Mile High Scribes: http://www.milehighscribes.acfwcolorado.com/
WWW Worship Write Witness: http://www.worshipwritewitness.acfwcolorado.com/
ACFW Arkansas: http://acfwarkansas.com/
CenTex Chapter: http://www.centexacfw.com/
DFW Ready Writers: http://dfwreadywriters.blogspot.com/
OKC Christian Fiction Writers: http://okcchristianfictionwriters.blogspot.com/
WIN: Writers of Inspirational Novels: http://www.win-acfw.com/Writers_of_Inspirational_Novels/Welcome.html
Writers On the Storm: http://acfwwritersonthestorm.blogspot.com/
ACFW SF Bay Area Chapter: http://sites.google.com/site/acfwsfbaywriters/
CWOW: Christian Writers of the West: http://christianwritersofthewest.weebly.com/
Find the right contest for your manuscript and you may find just the help you need to get your book published.