What is the difference between a trot and a jog ...and is there any difference between canter and lope?
I think it is just speed and cadence.

Does lifting your hands make you sit straighter when cantering?
I don't think it is directly related but lifting your hands helps collect the horse.

Also...does jumping jumps with one stride in between them help slow your horse?
I don't think so, but I think it usually sharpens you and your horse up.

Oh and one more thing...When tightening the girth on a western saddle...if there's no buckle, how do you tighten is securely?
I remember it 7+4=11. It's too hard to ewxplain without pictures so I'll see if I can find a web site.
http://www.western-saddle-guide.com/...ern-cinch.html
The steps make it look like a 7, then a 4, then the two straps are supposed to look like the 11.