Sorry - stream of conciousness alert:
A lot of good advice here. Never underestimate the impact of lots of small spending that really adds up and could be cut down/out without a huge impact on your lifestyle.
Food and drink out of the house/takeaways is a biggy. People can spend hundreds of pounds a month on these, which is thousands of pounds a year or tens of thousands of pounds a decade. So try to avoid it where you can. If you don't want to cook, look for cheaper equivalents in supermarkets, some are perfectly decent.
Likewise clothes, and bits for the house. Apparently there are people who buy new Christmas decorations every year, or are always getting new cushions, bedding etc when they already have what they need. If you don't need it, save the money instead - better for the planet too. Aim to be a 'low consumer' of stuff.
Putting aside the people who don't have enough money to afford the basics, and those who will never run out of money, most of us are in the middle, where a lot of our financial comfort is down to decisions we make about spending and doing this wisely by not spending where possible, and if we decide to do so, making sure we get the best price, is the main factor in how far our money goes and how much we have left to generate wealth after the money we've spent.
Cars are another one. Think of the difference in cost between running a small, lower spec, basic branded, efficient car vs a larger, prestige brand, more thirsty, higher spec version. Yes, the latter is more comfortable, but they both get you from A to B but a more basic car is hundreds of pounds a month cheaper.
Then there's hair/beauty treatments etc - something else that could be costing tens/hundreds of pounds a month that's slowing down becoming wealthy.
There's a lot of luck/right place/right time at play too. Anyone who's got in and out of a buoyant property market at the right time could have a massive six figure boost to their wealth that's simply not been available to many, no matter how hard working/enterprising etc they've been. So always be mindful of comparing yourself to others who may have had different opportunities to you.
If you're a single parent without qualifications working multiple jobs to try and make ends meet, you're less likely to be able to retrain into a highly paid career or make money in property, but there are things you can do to improve your situation that might pay off later, eg have egg on toast (or whatever cheap low effort meal you enjoy) instead of a takeaway, make sure you pay as little as possible for things like mobile phones, etc etc.
Don't be a brand snob, it's very expensive. Is your preferred brand really worth the extra money. In Eat Well for Less, in just about all cases, when they did blind tests, the participants couldn't pick out 'their' brand, that they had confidently declared was the only one they could possibly eat and often preferred a cheaper one.
Loads of ways to reduce your spend by a few quid, that if you make a habit of it, can free up hundreds, or even £1k+ of pounds a month for other things or to add to your aim of being wealthy as you can only spend each pound once.
If you're a spender, you might see the above as 'miserable' or 'what's the point' but if that's you, you'll have to accept that, unless you already have a lot of money, you'll probably never be comfortable/wealthy because you're always spending and you'll never run out of things to spend your money on, so your money will probably never exceed your desire for 'stuff' unless you change your mindset. I don't know if this is possible, because I genuinely don't want much stuff. I buy what I want, and it just happens that what I want isn't very much.
Someone upthread mentioned Stoozing - I've done this for about 15 years now, not particularly enthusiastically, but now that interest rates have risen again, I'm making a few hundred pounds a year. Related to this for anyone who has a low rate fixed mortgage DO NOT RUSH TO PAY IT OFF. Put the money in savings instead and pay it down only when your mortgage rate exceeds your savings rate. When we had a mortgage, it was effectively interest free and at some times actually made a profit because the rate was between 0.5 and 1% and we were getting 3-5% in various regular savers and current accounts.
Defintely use a cashback (or cashback-like - eg rewards for a shop you use anyway) credit card for all your day to day spending (paid off in full every month). Avios ones might be more beneficial if you actually would use the flights that you can use the points for and they're available when you want them.
But this is something I've never bothered with because we tend to fly from northern England to Europe and the choice for these routes is very limited and mostly non existent. Then it sounds faffy to find the flights at the right time - it will probably be different if you travel long haul from London airports and plan far enough ahead that the right flights for points are available. But we rarely book anything more than about 3 months ahead and often it could literally be more like 3 weeks - benefits of travelling outside peak times and being flexible about where we go.
Surprisingly, I can't see any mention of compound interest on this thread, definitely something to make sure you understand and appreciate how it can benefit you. Likewise investment growth over time and the importance of picking funds that charge lower fees, because the effect of higher fees over time can be significant. Behind all those higher fees are often a lot of highly paid people who's salaries are being paid out of your money.
Other things to add - the financial flowchart is excellent as a 'to do' list for your path to wealth:
https://ukpersonal.finance/flowchart/
Plus the Meaningful Money podcast, the current series of which is discussing the above in detail, so a good place to start.
https://meaningfulmoney.tv/
I'll shut up now - hope it helps the thread.