1
Check the friend requester account to see who this person is. take note of the people added on their account. If there's comments on the users profile read them. Now if their account is private don't add them unless you're willing to take the risk. People with profiles with Level 0 Private of unfinished setting up accounts are usually scammers.

2
If you added someone you have no clue who they are chances are you still have a chance of not getting scammed. If they send you a message right when you add them delete them because most scammers will send a message saying their friend wants to add you and they can't which is complete bs and they will link you to their account spelling steam community wrong. If you are adding a Bot for trading check their account first and check their rep. If you need to make sure check their inventory to see if they have the items you are looking for.

3
Rarely unless you got rare and pricey items multiple friends requests will pop-up at the same time and this is coming usually from someone who is controlling steam bots that are waiting for you to accept to then take over your account. Do not add them and block them from ever asking you again.

4
Added 5/15/2015 *
[Unassigned]

People will try to add with names that don't make any sense and what is most common is [unassigned], names with [Trader] at the end, that is either a private profile or shows up with a VAC ban on their profile.

Be Aware Of Profiles With These Avatars





These were most common friend requests to that I have seen so far.



Here's a glimpse of the amount that the Gaben avatar were used that I blocked.

There are thousands of scammers around the world just waiting for the fools to add them and trade scam them do not be the fool the will want to talk to you nicely to trick you in thinking you are friends and they will want to send you offers that seem good but in reality are total rip offs. Be ready for the world of steam if you are going to be a collector in items because once people find out about your account have very expensive items they will spread the world to their other buddies to try and scam you.

Here are some other small notes to tell of they're scammers.

- Their gameplay.
If they played only 1-3 games on steam and its says last played on 2009 its a scammer. Doesn't matter if their profile says 5 year old steam account its still a scammer. ( seen some accounts floating around saying last played in 1970.)

- Steam Rep
if you want more trust on their account and see if they ever got VAC Banned check Steam Rep.
Check if any of you're friends or friend requester ever got banned on Steam.
Steam Rep[steamrep.com]

- Don't Be A Scammer
Don't be a scammer around the the community telling people online that you scammed the fool a Scrap for a Earbud because you will be reported and if you think that you will just create another account and do the same cycle over and over you will eventually give up and be caught getting banned and have all your items end up being useless so don't be those people.

If i missed anything that you think is also scamming and isn't noted above type it into the comments below so that people including me can read and take notice.

[NOTES] The steps taken is this guide are all experiences I've seen happen to other people including steam friends and don't act like "ha ha! You got scammed!" " now you're screwed" will help because this will eventually happen to you if act all high and mighty.