Pitching is an art form.
I did it for several years when I was a newspaper editor, in daily editorial meetings. I pitched my reporters' stories, jockeying with other editors for more inches and page A-1 on Sunday, without over-promising or over-hyping the reporter's story. Writing the one or two sentence pitch, knowing the writer and the story well enough to promise what was realistic, is part of the craft.
So, you think your MS is ready to pitch?
Try Pitch Wars.
I believe selection has already started for this year, but now's a great time to plan for this time next year! (What can I say? I'm a planner and I need goals.)
Read the rules. When mentors are announced, figure out which ones like comps to your MS, or can offer your writing that needed boost, and you get to pitch to three for free, a fourth for a fee. There's no guarantee your MS will be selected.
All pitches are public and you cannot be agented for the material you're pitching.
I had hoped to do this one this year. I wrote my fingers off trying to get to a point I'd feel comfortable, but I didn't quite make it. I'm holding off this year. Next year -- hope springs eternal!