I have sold stuff on CL with no issues, expensive guitar included.
In addition to that excellent advice already given (cash only, meet inside a public place, etc...), write up a bill of sale, make two copies and both of you sign and date it in blue ink.
Something like this,
I, <your name> sell my Canon 10-22 EF-S lens, serial number <######> to <buyer name>, AS IS.
The "AS IS" protects you (in my state anyway) from the buyer assuming any warranty is expressed or implied. No buyer should have a problem signing this, it protects you both.