From your inventory list, click on an item you have already created, press "duplicate" (top left on grey bar above actual inventory list), choose how many duplicates you want, then press OK. Click on the duplicate item, then press edit (2nd icon from left (beside NEW) up near the top (second grey bar). I find it pretty quick. Be very careful to read and edit each and every line...it's pretty easy to forget to change your title or forget to change postage...

I would advise only creating 1 duplicate at a time, if you get distracted you may end up uploading more items than you have to sell.

When uploading, make sure that all your items are highlighted (you'll have to scroll up even if you think you already did). Hope this helps!

I don't use the template function, but I do my listings in different folders that allow me to keep track, which is easier for me.

I have one folder with a bunch of sample items, in which I have the category selected, with price and so on at the usual that I pick for that area and my description text already has my Terms of Sale.

As I'm about to list, I put all the items that I'm going to list in a new folder with the date and the word DONE in it. That way I have to physically move a listing from the original "working" file to a "completed" file. I find this makes me more careful and is a nice double check on my work.  If I'm not done with a listing I also tend to write something in all caps in the TITLE, so I won't accidently list it (although it has happened and even sold!). Like NEED MORE TEXT, or NEEDS MEASUREMENTS or whatever. 

Then I can take all the items in that folder and upload at once. And I tend to do that when I have some critical mass -- I think TL is more likely to mess up with bigger files (okay, this is just a perception of mine) and so I would rather do two uploads of 30 than one of 60.  So when I get to 25-30 items, I usually go ahead and upload. Then I create a new DONE folder, so for some dates I may have 3-4 done folders.  This system works for me so I can keep track of my listings and those in progress.

I always type of my listings in Word first because that is faster for me.

Then I just duplicate my sample listings and cut and paste my listing.  If you write your listing to start with the title, then you can just cut and paste right into the title field and then go to description and paste again. This goes pretty fast.

I can quickly change anything in the listing -- postage, start price or whatever.  I did 29 listings yesterday in about 30 minutes of cutting and pasting (had the descriptions already written). Then uploaded and done!