Start off with clothes you avoid wearing - needs ironing every time you wear it, keeps slipping down, keeps untying, has never looked right - all this can go.
Next start on the clothes you like, but need tweaking - need shortening, need buttons, needs dry cleaning, needs mending - and honestly ask yourself, can you afford the time, energy and money to make them wearable.
If you can, put them to one side, those that you can't, send them away.
Clothes you like - how many black t-shirts do you need? How many white blouses do you need?
Go through them critically and ask yourself if you're cycling older garments and keeping some stuff for 'best'. If 'best' is never coming, get rid of the older garments and make yourself wear the good stuff.
Shoes - pair them up and put them on. Do they rub? Are they painful? Do you have to cover your feet in padding and plasters to stop you limping before midday?
Get rid of any you can't fit all your toes into, any shoes that still have blood stains from when you last wore them and any that you ended up taking off in the taxi home. Life's too short to cripple yourself.
The shoes that are left - do they need mending, polishing or cleaning? Is it worth the time and effort to do this? If not, get rid, if it is, keep them and put a definite plan in place to get at least one pair a week to the menders or plan time to clean and polish them yourself.