Here is how to get the best price for your machine. If you are uncertain as to what you have, what the accessories and other parts are I can identify them for you and prepare a suitable  advertisement. You might then like to take advantage of my advertising page to sell your machine http://www.lathes.co.uk/page3.html - it has a world-wide reach, a huge readership and, if you Google "lathes for sale" or milling machine for sale" etc. it's often the very first hit after the paid-for links..

You can also advertise directly online here: https://store.lathes.co.uk/adverts  The contents of that page and a link to it also appearing on the page mentioned.

If writing your own description be honest.
Give the machine's capacity: for a lathe this might be expressed as 125 mm x 500 mm (125 mm centre height with a capacity between centres of 500 mm) for a milling machine the table size and travels expressed as: "power-feed table 150 mm x 750 mm with 1000 mm of longitudinal travel, 300 mm in traverse and 500 mm vertically.
Look carefully at its features and specification and list them, for example: the spindle speeds, screwcutting ranges and power-feed rates (displayed on plates attached to the machine)
Include, if you know it, the history of the machine e.g. "Ex-university research department"; "one owner from new"; "used only for model engineering"; "utterly worn out having been used on 24-hour shifts turning hardened steel billets", etc.
Read some of the descriptions on the lathes.co.uk sales page for some well-written examples.

Getting it ready:
Today, it really helps to have some clear, close-up high-resolution pictures of a machine that has been cleaned down and with rubbish, old tyres, broken bicycles and other workshop detritus removed from around it. Clear the machine of odds and ends; remove pictures of naked women from the wall behind and tidy up the shelves. If the machine is grubby a simple way to clean it is to use white spirits. Use a stiffish 2" brush and wash the machine down from the top. Really engrained dirt can often be shifted using one of the many propriety kitchen cleaners--but do test first on small area, they can be quite harsh and remove paint.
The best pictures are of a machine set the item against a plain a background or, if this is not possible, try to blank out what's behind using large cloth sheet, large pieces of cardboard - or similar.
If necessary, before taking the pictures, get some extra light into the workshop, it really does help.
Today either a digital camera or phone is fine - but do support your chosen device on something solid, it can make a huge difference to the sharpness of the image.
Take a series of pictures showing::
1) the whole machine including the stand (if fitted) from the front, 45° left and 45° right.
2) if the machine is on a stand, repeat the sequence without the stand showing
3) take close-up pictures of the main, individual sections. e.g. for a lathe that would be the headstock, the whole carriage, the cross and top slide assembly and tailstock. For a milling machine, photograph the side and front faces of the main column, the front and sides of the knee and all around any vertical head fitted. Here is a link to " lathe names of parts"
4) open covers and photograph inside them (you might have to do some cleaning out first…
5) photograph any plates showing spindle speeds, screwcutting ranges, etc.
6) a set of close-up pictures of accessories is also helpful (you may find searching through drawers, cupboards and on shelves turns up things like faceplates, gears, chucks and steadies, etc.) If you are unsure about an item belonging to the machine tool, just send pictures anyway, I'll be able to identify the parts for you.
7) this is a decent if not perfect effort: http://www.lathes.co.uk/advertphoto/sampleadvertisement

Occasionally accessories turn up that are rather valuable and can be sold separately - again, I'll advise if this is the case.

When sending photographs it's a good idea to email them at full resolution, not downgraded for transmission - they can then be worked on to get the best possible image. If your email won't cope with large files, you can now transfer them very easily indeed using the program "WeTranfer"  https://www.wetransfer.com
Just click on the box that appears on the left of the screen - there no need to sign on - and attach the pictures. Up to 2 Gig can be sent at once. It really does work well - though of course you might have to wait several minutes (or longer) for the upload to take place.

Just after sending the pictures please phone to let me know - we receive so many emails that it's not always possible to keep up.
The cost of advertising is modest: £32 + VAT = £38.40 for each significant machine tool (though simple items like drills, etc., can be grouped together in one advertisement), up to 200 words, 8 linked pictures and a duration of 6 months. A link can is also included to the relevant page on my web site to give potential buyers the chance to read a detailed technical description of the machine. If you would like extra pictures these are charged at £1.20 each including VAT
I take no commission, only offer advice as to what you have and a likely selling price, write the advertisement (if you wish), trim and optimise the photographs and post the material on the site.
Do phone if you would like to discuss any points. 01298-871633 email: tony@lathes.co.uk
Payment can be by credit or debit card, cheque, postal order, bank transfer or PayPal.

What happens when people call to see it?
It's normally assumed that potential buyers will call to inspect the machine, negotiate a price and either pay in cash or leave a cheque to be cleared through your bank. They may also offer to transfer fund  from their bank account to yours and, of course, if you have online banking you can check immediately to see if the transfer has succeeded. They may also opt to pay via PayPal; if you don't have a PayPal account they are simple and quick to set up. If you think somebody is trying to scam you, phone 01298-871633 and I'll advise.
It's wise, as you won't know the caller, to remove and loose, easily-stolen items from around your workshop; things like micrometers, verniers, spanners, etc, have all be known (very, very occasionally) to disappear.

Selling on behalf of somebody else:
We are approached, with great regularity, by gentlemen who have been asked assist in clearing the workshop of a deceased person. The first and most vital thing is to tell the owner that she (it's usually a female) should, under no circumstances, sell anything until I've had a chance to offer advice about likely selling prices. In the past I've come across many situations where dealers have attempted to "steal" the goods and (unbelievably) even neighbours have even claimed:  "They're worth nothing, but I'll give you £150". Unfortunately the continuance of neighbourly good harmony is then somewhat strained when the machines sell for over £2500.