I just use a liquid glue that dries clear, like KI Gloo. I turn the item to the back side and put a thin layer along the paper edges, then put it on the LO. I apply just a little bit of pressure. Mine have all stuck fine using the KI gloo.
I've used Tacky Glue, I just smear a bit where I want the item to go and press it lightly down. I don't see the glue when its dry and I can even manuever the item slightly after placing it. Then it stays put!