Could anybody please give me advice about what to wear/how to come across more assertive?

[Afriendinneedsafriendindeed]

I basically live in leggings and comfy clothes. Never wear make up as I can't do it very well/don't know what colours suit me.
Do beauty counters at Boots still offer free makeovers?
I am 31 and sick of being the shy person who is passed over for teaching jobs, and generally not that well respected, mocked by 'friends'.
Sick of feeling nervous when I speak and self conscious.
I own a few blazers, but I really don't know what to wear otherwise.
I have a pixie cut that has been growing out for 11 weeks so it's basically nothing ATM, just that awful in between stage, I hate it.
Apparently I always smile when I speak too, which I know isn't bad, but I'm maybe taken less seriously.
Just had enough

Also on a low budget, so looking more at Primark/charity shops to be honest

I dress like a tramp and everyone's scared shitless of me.

I think you're focusing on the wrong things. Whilst clothes can give confidence I think you'd be better off working on what's on the inside.

What's wrong with smiling FFS? Who are these weird people you listen to?

I really agree that you are focussing on the wrong things.

Grow your confidence and your dress sense will follow. I would spend on assertiveness/self help books and apps before you spend on clothes.

I’d say a smile gives an impression of confidence so don’t stop doing that! However, a lot of women will sound more confident or assertive if they make a point of lowering the pitch of their voice - I’ve been a telemarketer for many years so this is something that is engrained into me. Also try not to rush or gabble what you are saying - take your time - and don’t give a rising intonation at the end of a sentence - it tends to invite a negative response. So that’s for ideas, none of which
will cost d a penny.
For make up, beauty counters do give makeovers although the usually expect you to buy
something or you could look for online tutorials or buy a book. Also, some products come with handy guides eg diagrams of what to put where. However, if you’re talking about teaching, you probably need to keep the look simple and professional rather than anything outrageous!
Clothes-wise, a blazer is probably a good staring point. Add some smart trousers or a skirt and a simple top and accessorise with a necklace/scarf/belt/brooch and you’ll be fine. For shoes and footwear bear in mind you’ll be on your feet quite a bit!

Toastmasters in my area encourage people to join their meetings and basically practice public speaking at their meetings. A friend has done it and found it excellent, these people speak professionally with an emphasis on directing and leadership.