That book I mentioned is good - but quite a read.
You can start with the website I linked; http://www.ahaparenting.com/
There is sooooo much great info there for every age & stage.
There should be no reason for a sitter to treat kids differently except according to their ages & differing needs. Otherwise...this concept is just about respect, teaching & kindness & hopefully she will be that way to anyone in her care. The best you can do is just ask he what she does & see how it aligns & then give your input on what you'd like to see & she how she responds.
I feel you about the daycare. it' shard. The one momma (with the spitter) is really sweet & has thanked me for taking him as not all places want to deal with those outbursts or be kind about it. Honestly though - if you stop taking it personally & just see it for what it is (an unhappy kid) it is much easier to empathize & try to thelp them find appropriate ways to show you how they feel. A happy kid never does that stuff. Somehow that seems like a no brainer to me. ;)
I am SO sorry BTW that you can't even trust your mom to watch your baby. That has to be very disappointing & frustrating for you.