hahaha this isn't expert manipulation, this is just level 1 here in steemit :p
I think you can easily understand who most of them are just by looking at their comments or the private message that they sent you. Now let's move to the next leve in which as you said they use great comments only to seem nice to you.
If they ask you something in private that is related to ''help'' by voting them cast them aside. Later on if you aren't sure about someone you can easily check his posts, wallet and comments. From that i bet you can learn a lot for that person. Finally, if still you are not sure you can ''test'' them by not upvoting their comments or by upvoting some of their posts with extremely low % like 0,01$ and see how that goes.
You can easily flag some of them though or click not to see their comments. It won't solve the problem but it will give a message
You think I fall victim to this comment or direct message shit? Don't insult my intellect.
I am not that gullible, now you know.
(erased the first part to protect people)
i never said or implied something about your intellect. It was a general comment to something that 's basically happens to anyone having a bit of SP and then suggested some things that could be done. The ''you'' part is for the message to be more direct to the reader.
No worries : )