If you haven't worn make up ever at 28 start slowly.
Agree with the eyebrow threading - it really does make a difference having well shaped groomed eyebrows.
Maybe try getting your lashes tinted too.
Try a semi lipstick or sheer lipstick (many brands do them) in a natural shade. These aren't as obvious as full lipstick, but have more colour and staying power than tinted lipbalms and aren't gloopy like many glosses.
I've found Mac sheertone blushes hard to overdo - They are lighter than a lot of blushers so it's easy to give a wash of colour without going overboard.
As for anything else buy an eye pencil, an eyeshadow and a couple of brushes and just play around when you have an hour free.
Start aiming for a natural but groomed look and then when you are comfortable wearing make up you can maybe be more experimental with colours/looks.
Skin care routine; Keep it really simple. Maybe start with a face wash and moisturiser. Or micellar water or a light cleansing lotion you can rinse off. Try ranges such as Simple, Bioderma, Avene, La Roche posay, Dermalogica.
If you visit a make up counter for advice their job is to flog as many products as possible so be warned!
Lisa Eldridge has some excellent videos on her blog.
'Makeupalley' is great for product reviews and info'
Bobbi Brown & Clinique do good make overs in stores but don't feel pressured into buying everything.
Buy a good blusher brush and eyeshadow brush to get you started - good brushes make it so much easier.
Thinks I'd avoid at this stage are multicolour eye pallettes, buy a couple of single eyeshadows and don't go for fancy shading routines straight away. You'll never use all the colours in a pallette anyway so it's a waste of money.
Aim to look yourself but better - emphasise your eyes and lips, aim for a brighter fresher complexion.
When you are familiar then start to play with all the options - cats eyes, smokey eyes etc.
And remember it's only makeup, it cleans off!