Even pictures of the flat item are helpful if you don't feel comfortable showing your body or it's something you can't decently appear in without being nsfw.
Look at the quality of the seams - any fraying or loose parts? Any bits of it itchy? Measure things. If straps or stretchy parts are adjustable, give the minimum and maximum measurements. If you're comfortable giving your own measurements and comparing it to the size chart this is helpful. "I have a 41" bustline, which makes me a 1XL in this brand, but I only have B cups, which left some gaping in the bustline of this product" is the kind of comment that is helpful to buyers.
Talk about the feel of the fabric and the care instructions. If it says hand wash only, and you cheated anyway and washed it in the machine on the delicate cycle, how did it turn out?
Is it a good value for money? A $70 bustier should be held to a higher standard than a $20 one.
How easy it is to get on and off by yourself? Not really applicable to things like babydolls or nightgowns, but things with lots of straps and adjustable bits might qualify.
Did it make you feel sexy? If you wore it for your partner, how much did they like it?
Is it comfortable enough to sleep in? For bras and panties, do you wear them everyday as a sexy secret under your work clothes or only put them on for playtime?
If it's a costume, did you use it for any roleplay, or was it just the visual appeal of the french maid / sexy schoolgirl / naughty nurse?
Quite often, the official photos don't show the model from the back. If this is the case, even if you don't have photos, try and explain in words how it looks from behind. I always hate not knowing that!
Hope this helps! I should probably grab all of these notes and put them together with some information about different types of fabric into a tutorial. I love talking about fabric and clothing.