I will try to make it short. I have been successful investing for a long time(10+ years), long-term and having no background in finance or whatsoever. Read it only if you want to invest it in the long term, possibly forever, so you acummulate assets over time.

My tips/rules:

- buy some books about value investing and read them(don't only buy)

- NEVER buy stock from recommendations

- avoid mainstream media about finance if you can't take it 100% as entertainment. I currently only laugh at analysts when I see it, for instance

- if you mess up, sell it and accept that you lost money

- don't invest in risky stuff a huge percentage, you first need to understand your emotions and how good/bad you react when it falls. this is something you can develop in many years of investing

- as a beginner, have at least 3 types of assets(government bonds, REITs, stocks etc)

- of those at least 3 types of assets, never have 10% of more than any

- feel free to buy crypto, but don't put over 10% in an asset class(crypto)

- don't buy things which you would want to check prices regularly, humans can't handle it

- would you lose your sleep if you lose 3k out of 30k? if so, diversify more

- prefer stocks over indexes, but in the beginning, considering buying a lot of indexes and some stocks you like for you to get the feeling, also other assets types as I've mentioned above

- have at least 80% invested in simple and boring stuff(and change that when you are more experienced, but now, you are a terrible investor, I still consider myself a terrible one).

- create a google spreadsheet and keep track of everything you do. have one sheet that has all the transactions you made, reasoning(why?), prices, mood etc. you don't need to make it fancy, if you have it all listed, as I've told you do to do, you can always create other sheets based on this info, such as tracking your performance etc
- avoid tracking your performance, warren buffet got like 17% yearly over a few decades and he's the outlier, don't expect to make more than this and also don't go for opportunities that are too good

- learn how to read a balance sheet of a company it will be good also for your working life

- try to invest every month a value, rather than in big amounts, like in fitness, if you want to get fit, going to the gym everyday is better than going once and working out for 12 hours(good luck with that)

- don't do trading, it is a zero sum game

- don't forget that you aren't smart and much less smart than the market, so don't try to be smarter than anyone

- save and invest, but don't go to crazy about it

- don't move your assets around(selling one and buying other) too often, give yourself limits, like 10 times a year. I haven't sold a stock for 5 years and I'm doing well, I promise.

- don't talk about investment with friends or share your gains, you want to make money and grow your assets, not receive some attention you didn't receive from your parents. I see a lot of people doing this mistake and people can either start to be envious of you, or recommend you bullshit, so just say that you invest in some stuff, or even don't mention it at all, if people ask.

My investments have outlived everybody "I personally know"'s trading career and people are now kinda of envy I took the path of taking it slow and accepting I'm dumb. I just accumulate. I don't believe anybody can make money consistently, for a long period of time, doing trading. Avoid trading. Feel free to try it with very little money, so maybe you lose and give up, or if you win(the worst lesson you can get), give it time, you will eventually lose.