After many years of doing this, these are actions to follow when selling stamps on eBay:

Include country name in title, even if where you are putting it is country-specific.
Include the date of issue, it may have been someone's birthday.
Do not include catalogue number in the title - nobody in the US is going to have a Michel catalog for US stamps, likewise nobody in Germany is going to have a Scott catalog for German stamps.
Do not include catalogue price in title, include in description, if you must, noting catalogue and when it was issued.

Nobody in their right mind is going to believe the following phrases:
Found in the attic.
Belonged to my great grandfather (substitute appropriate ancient relative).
Collected 50 years ago when I was a kid (they are probably worth the same, or less today, given the cost-of-living increase).
Estate sale, unpicked.
Write "I know nothing about stamps" - it will be obvious to potential buyers if the stamps can be bought more cheaply and used for current postage.

Include the condition of the stamp(s) in longhand: mint, hinged, used, cancelled-to-order etc.
Give brief description of what stamp portrays.
Do NOT use "see scan".

Read, and pay heed to emails while the auction is in progress.
Respond to emails regarding information within the auction text which question your description and which you think will enhance their value.
There maybe some highly speciallized stamp collectors out there that know far more about what you are trying to sell, than you.
On the other side of the coin, there are probably always buyers who would like to get a bargain. And try to pull a "fast one" on you. The only way to be successful is if you are more knowledgable than they.
That requires both work and experience on your part.

Do not photograph stamps unless you have a very high resolution camera.
Scan individual stamps at 600 dpi, groups at 300dpi and covers at 150dpi.
Do not overlap stamps in the image. Viewers want to see that they are all intact.
Do not show stamps in stocksheets which hide half the stamp, same reason.
If you must use it, adjust your image size to make full use of eBay's Ipix.
Preferably, use your own IP and make stamps average less than 100k in size.
Do not include multi-images which take 10 minutes to load.
A single image with links to the other 30 or more will suffice.

Explicitly outline the mailing cost.
A single stamp can go very cheaply via first class mail.
A hundred stamps can go for the same price.
Include extra charges for registered and recorded mail if buyer wants to use that OPTION.
State whether multiple buys will be delivered in same package for a single cost, or not.

Use spellcheck or equivalent before submitting your auction for sale.

If you are multilingual, avail yourself of your abilities.
The same material written in two or more languages can reach a much larger audience.

Remember, eBay is about worldwide stamps, not US stamps.
At least half your potential buyers do not live in the US and may not speak English.