Loads of good tips here.
Not read the full thread so apologies if this has already been suggested but quite honestly the thing I've found most useful when money is really tight (and when I'm not housebound so likely to be spending more) is to use cash
Wherever possible!
Seeing it spent and reduce in clear physics terms really makes an impact
I've even done separate purses for separate budgets at points - a purse for groceries, a purse for clothes and shoes, a purse for dds needs, a purse for personal stuff...
And when that money for that budgets gone it's gone!
It's so so easy to spend now with cards and transfers and contactless - in a way that we're psychologically distanced from our spending I'm sure it contributes to the level of personal debt incurred.
But yes I also do all the things like review utilities and other services regularly (although I'm finding it very hard to leave my gas & elec supplier) and get rid of subscriptions when I'm no longer using them enough.
And when planning infrequent purchases I try and find the best quality for the price I can afford. Make use of special offers and sales periods.
Not just wait until sales but use sales for "pre-emptive" buying eg when dd was little I'd buy her summer gear in the jan sales and her winter gear in summer sales - until they're teens they're not that fussed about fashions and the styles actually don't change that much in a 6-12 month period!
At one point I bought 3 winter coats in a great sale in mothercare that did her the next 3 years for less than £5 per coat!
I also do spreadsheets and balance them with my actual spending - if anything I've a bad habit of trying to set myself too strict a budget that's impossible to stick to and stressing myself out
I also struggle to remind myself inflation exists and find myself trying to stick to the same budget for a category for years on end!
So it's good to review and occasionally actually increase a category as is realistic.
Anyway hope the thread and my post are genuinely helpful to you op and maybe others too