Need help with duping

I don't know how you people do it, but I've been trying for over 3 hours now. Fingers hurt so much lol, anyways I have not duped a single item. Please it would be very helpful if anyone can provide any helpful insights to proper techniques, heck even tips would benefit me so much. Thank you!

I hate to ask like this, but if anyone else can spare me a duped item they made? Just one, I don't have anything good to dupe lol. It's alright if you feel that I'm beggy, please don't feel obligated. Thanks again.

I'll be duping Resu Armors, I don't mind if you get one