I am in no way a pro but I have been selling for the past 2 years and have been moderately successful.
To see what an item might be going for you do a search for the item and check the completed listings box. It shows what items sold, for how much and the items that did not sell. You can usually tell why they did not sell - it is usually because they asked too high of a starting bid or didn't have a picture.
This is how I do shipping - I put the item in a box and weigh it on our regular scale. I
"guesstimate" to a little higher weight and then have the buyer calculate the shipping from my zip to their zip. I do not charge handling but some sellers do- it is up to you. I go to USPS and order their boxes- they ship them to you free and they do not charge for the boxes. Some items I use the flat rate boxes so it is easy to determine shipping that way!
You can ask whatever you want for starting price but if it's too high it will turn some, if not most buyers away. If something is valuable and you are pretty confident it will sell for large amount you could just ask a fixed price.
I hope I helped in some small way. Once you start it gets to be easier and easier. Good luck!!!