Dropshipping fail

First time trying drop shipping, i got a product that no one else is selling from what i can see(Female fashion). I've spent around £100 in google ads and £50 on instagram.

So far i have no sales. Where should i be promoting my store ?

i don't dropship tbh. I dunno if I'm in the position of giving u a piece of advice. but based on my humble knowledge. firstly, people are promoting their products on Facebook. running ads on Facebook will cost u less than what it costs u on google. Google Adwords is hella expensive. especially for u if u're just starting out. + u have to test multiple products on different audiences. it's all about testing. Try to check ur store/ads/product. u will learn from failing and losing money (this is something that i tell myself too. because it's a fact). Anyhow, good luck in ur journey towards financial freedom.
PS: for Instagram try getting shoutouts from influencers or other pages. i rarely see people running ads on insta at the beginning. i dunno. Go search for more information about it.

If there's no competition on that maybe it means it doesn't actually sell, you can try buying shotouts on IG find some fashion related profiles targeted audiences and test, you never know when you gonna stumble upon a winner product just test

the product that no one else sell is a bad product and vice versa

I wish that this would be so easy. 3 most common reasons why u fail most probably are that your website is bad, no proper campaign setup and people are just not interested of that product. U need to have very trusted looking website and highly targeted traffic from your campaigns (no broad match kws and so on). Reading your post it looks like u wanted to make quick money but forgot most important things that needs to be figured out before starting to spend funds on ads. But 150 GBP is just a small loss.

it's nothing for 150 gbp

If it's a new product that nobody ever sees then you shouldn't use Google Ad. Google ads only works when people know your product and search for it. Instagram is fine to build some product awareness. You might also want to try facebook and pinterest for that matter.

From what you said I think your problem is the fact nobody else is selling it. First you will have to do a influencer/product launch campaign and then you can sell it.