I think the one you mentioned, "Losses are part of the game" is the most important. It builds character before anything else. Strategy is the easy part since it's all in the mind, you can research, copy others, or learn through experience. But if you're not disciplined enough to accept losses, then everything you've learned becomes useless, because you won’t be able to execute your game plan properly.
This advice also works on all aspects of life. From our failures we gain the experience and learnings so that we could avoid the very same mistake we have committed.
In general, cryptocurrencies are form of investments. It is nothing but normal to lose money in the process especially if you fail to consider several factors on your investments. The key in making the most out of our investments is by being patient. Due to the nature of cryptocurrencies (specifically BTC) that has a limited supply in the market, expect its price to increase in the future.
If you are, OP, talking about cryptocurrency, then all the losses that those who want to make money quickly will most likely not be compensated, and these people will get a lot of disappointment from their connection with some coins and investing in them. First of all, you need to clarify what you are writing about. If it is Bitcoin, then with the right holding and patience in investing, you will not feel remorseful for investing your money in it. Therefore, OP, before advising beginners, you yourself should correctly distinguish one from the other, and only then make such guides.
Instead of seeing your investments that failed as "losses", see them as experiences where there is an opportunity to grow. Like what they always mention,
charge it to experience and make all of those learnings part of your system and process.