First way to avoid getting scammed is to be Skeptical about everything, and unsolicited private messages or DMs should be treated with Skepticism hence if otherwise any dreams sold to you by anyone should not be bought, don't hesitate to leave such conversations that have too much of promise of returns to you.
it is not even about not buying into anything that looks too good to be true but rather, it is about doing proper research on anything before eventually investing in them. be it something that soesnt look too good to be true or something that looks too good to be true, still do your own research to be on a safer side. at least, the forum stands as a good option when it comes to making enquiries on what one should or should not invest in, and some, you can always fact check any project that you are about investing in on the forum and then you can be better positioned to make the right investment decision.
one thing is that most of the tokens that you see people sending to your DM are just scam project or else, they will want to run legit promotion on such project. even on the bounty section of the forum, there are project that does not do too well, how much more the regular one that a random person just sends to your inbox.