I've seen Youtube videos and articles recommending to "let your jig hit the bottom" and then pull it up a bit. Others talk about "counting it down" to depth, or otherwise knowing how deep it is.

Unfortunately, I haven't been able to find any information about how to know how deep the jig is. I can't even tell when mine hit bottom, and I certainly can't tell how deep they are when I'm retrieving them.

Also, if I start my retrieve at a certain depth, will the jig stay at that depth until it gets pretty close back to me?

I understand why depth is so important when fishing, but I just can't figure out how to use it to my advantage. Any tips for a newbie on all this?