Hi warjag1 , welcome!
(Prepare yourself for a long post . . .)
I tend to agree with NR about the variance in pricing. I have been collecting mostly my whole life but selling on
ebay for the last few years off and on (and buying, I can't help myself!) but I still don't really know what to price things at to guarantee a sale. I Have figured out that 22.5% of catalog is a starting place where you will most likely get a bid for an auction listing. But for Buy It Now as you are doing I am not sure. Sometimes you just have to wait for the buyer that really wants that item.
Good stuff always sells though. Condition, centering, gum, perfs as you mentioned, thins, creases, wrinkles, gum bends on older stamps, all can affect how a buyer perceives a stamp. On used stamps, if the cancel presses into or through the stamp too. There are many degrees of what is good enough for some and not good enough for others.
I am puzzler47 on
ebay so you can pick on me if you feel like it in case I blab on too much here.

I am selling other people's stuff but I am slow and spend too much time at it I think. It is fun to me though.
I find every once in a while it is good to take some time to look around at what other sellers are doing and see if they are successful or not using their way of doing things. It is good you are open to change and learning. Bravo.
So as long as you just keep to the facts and don't get all emotional over the niceness or beauty of an item (beauty is, after all, in the eye of the beholder) you will be OK. Any defects you should describe, especially if it is single stamps or higher value stamps you are selling. A scan of the back is a nice thing to include if possible. I like to do that but some (many) don't for lack of time and other reasons.
If you are selling a mint stamp (I noticed you used the
ebay word unused, which is technically correct, but in stamp collecting also can mean 'used on an envelope but not cancelled') it should be described as Mint Hinged (MH) or Mint Never Hinged (MNH) (MLH = mint lightly hinged) or just plain Mint in the Title in my humble consideration.
Putting the term Mint or MNH or MH in the title will help people find you auction. Do a search and see what word comes up more, unused or mint. If selling worldwide to overseas they use MUH (mint unhinged) or UM )unmounted mint) and MM (mounted mint) so the word Mint is always used (ha, a play on words there!) so always tell in the description whether it is hinged or not. Affects the price/value.
I like your photos or scans. Nice and clear and sharp and higher resolution. People will bid higher and more if you have more pictures and they can see what they are getting into, so to speak. Then they feel like they have made the choice themselves and figured it out as best they can (allowing for faults that are hard to see on scans, which you should describe, but don't dwell on them.).
Example, your Worldwide lot which is priced at about 5 cents per stamp might sell better or faster if you could spread the stamps out and face up so people could see what they are getting. You could use the word Kiloware or oz or lb or gr (gram) or kilo in the title and also tell how many approximately stamps there are in 5.9 oz in that lot. I know because I had figured out over years how many stamps I was getting in an oz of on paper stamps. But it is still nice to know.
The words 'off paper' or 'on/off paper' are always good to include in the title also as people search for that. The words lot or mix or mixture or accumulation or selection are all good words. Some sellers use 'nice mixture' or 'nice selection' for lots of stamps. That's OK as long as the stamps Are nice and not damaged.
Sorry if I am saying too much. I just have watched auctions and sales go south because they did not describe with searched-for words enough to attract a range of bidders or buyers.
As to shipping amounts charged, I see that you are using $2 US for shipping to the US. That is a bit high and stamp people (like everybody) are mostly aware of higher than need be shipping costs. It is OK and things will sell but not as many and not as well. I myself have not figured out how some sellers charge so low shipping regularly and still keep up with buying paper and ink and glassines and envelopes and stamps and packing and also paper work for the IRS if needed and time spent and coffee and donuts and old fashioned vanilla Laura Secord ice cream cones with a chocolate on top. Oops.

Well, you get my drift. I have seen sellers use $1.50 US, $2 Canada/Mexico and $3 Worldwide which is still a tich high but acceptable mostly. It's always a trade off. Some folks will understand and some will not want to pay any shipping at all, darn it. Combined shipping (and tell them How you combine) is always a Very Good idea. No need to make Too much off of shipping seemingly to the collectors eyes anyway. I know one does not make anything off of shipping because mistakes always happen and they have to be paid for somehow etc etc etc.
There, I am out of breath now. I knew I shouldn't have eaten that piece of fudge before I typed this! Sugar high. Must go sort stamps now to wear it off. A Lot of stamps.


