How to have a concrete "Give":
- Jackpot, give a lot of treats to the dog. My tip: use real meat. Give the dog a low-value toy. As soon as she picks the toy up, hold up a treat and say "Give". If the toy is low value and if the treat is high value, she'll GLADLY give up her toy. As soon as she gives up her toy, treat and praise. Another tip: Do this when she's hungry (early in the morning or late in the evening). Repeat repeat repeat.

Eventually, you can increase the value of the toy, but always make giving up the toy funner than the actual toy. For example, if she's chewing on a rope toy, say "Give". As soon as she gives up the rope toy, start playing with her. She needs to understand that whatever she gives up, she'll receive something even better. Ergo, she'll look forward to giving up her objects no matter how high value they are. The most important thing to remember is to repeat!!

ETA: Oh yes, luring. My advice - stop it. I don't like luring. Doesn't teach the dog a thing! Also, dogs don't know a moral right from wrong. When your dog isn't giving up certain inappropriate objects, it's probably because you're approaching her in a manner that causes her to guard even more. Instead, recall her and then command "Give". Also, implement NILIF (Nothing In Life Is Free) if you haven't been doing so already.