What would it be? I've done this for many years but still have yet to see one come in. I have tried electronic and hand calls but I prefer the idea of hand calls just for different sounds that hopefully they haven't heard.

Practice, I keep a call in the truck to practice on. Keeps peace in the house. When I was working everyday, to and from work was practice time. Put calling instruction CD's/cassettes in the player in the truck for reference.

Then when you get in the field you get the sounds you want right off the bat.

Practice and patience.

Find a call that’s easy to use, like a closed reed. They can/will freeze in cold, but are typically easier to blow and work than an open reed. Mix up the emotions, volume, duration, etc.

Increase your odds by calling to areas you know that has coyotes. Go out and scout for sign and listen for them to howl and communicate.

Don’t go into an area to call if the wind or conditions aren’t right. Let it be until the wind works for your approach and setup and have as many variables in your favor as opposed to working against you.

Unless you’re in wide open flat land with no cover, just because you haven’t saw them, doesn’t necessarily mean they haven’t came.

Don't get too caught up trying to sound like the pros. The beauty of hand calling is that you won't sound like all the rest.

Take your hand calls into places where others are unlikely to hunt with their ecallers. Use a shotgun if you have to. Jump fences or creeks that others won't.

If I had one tip.....IDK. Really I have several.

Like said above. Get one, practice with it, and don't be scared to use it. You have to use it enough to learn it, get comfortable with it, and give it a chance to work. Closed reed is easiest to learn with. Don't over call and try too hard. A nice moderate toned cottontail will kill a lot of coyotes.

The sound does not have near as much to do with success as the other 90% of calling predators. First, find an area that has plenty of predators with NICE FRESH EARS. I really can't stress this enough. There have to be predators there, and they have to be call-able and not highly educated. Really pay attention to your sets. Work hard on good setups.

If you are successful with an e-caller you will be with a hand call as well. If you aren't successful with an e-caller, a hand call is not a magic bullet that will change that. Even though, I do find that moderate/minimal calling with a hand call can sometimes net some animals that blasting an e-caller won't, just due to it being a totally different style sound than they are used to.

What I have said might sound brutal or condescending. I promise you, I do not mean it that way. Not at all. What I mean is that the majority of the time your location and setup is going to have way more to do with your success than the sound you use. There are exceptions to that, but it is a good general rule.

As far as blowing a mouth call I try and put myself in the shoes of the rabbit or animal I am trying to mimic. Realize they have small lungs. Put some hurt and emotion into it. Let them "get tired" or excited, or whatever. Experiment with the call, and how to make it do different things. Watch some videos, listen to tapes. How to use your lungs, mouth, and hands in concert together to change sounds, tones, cadence. Try and mimic what you hear, and then don't be scared to try something else.

Good stuff JTPinTX

One tip, eh?

Take your handcall to a large State Park, or other area where hunting is not allowed. Call the coyotes there.

Since they haven't been hunted, legally anyways, they should be easier to call. This allows you to study them, i.e. read their body language, as they approach, and will give you confidence, because you DID call in a wild coyote.

Take note of wind direction, the cover they came from, their approach angle to you, etc..

If you do this in late September/early October, you will be calling 6 month old puppies, that have only associated a rabbit squeal with Mama bringing home the bacon, and are so much easier to call.

I guess it is obvious not to bring a firearm if doing this.

Others have posted some great advice but one trick I learned is for practice. Take your e call and wherever you are put it on a moderate volume and play straightforward sounds then try and mimic it with your handcall. What this does is help you learn control of your calls and where to find each subtle change needed to really make them sing.