1.when drinking, 2 when gambling & 3 in the presence of women easily relates to your vices or daily practises & your new friends will often play along but be aware of their reactions to more mundane situations. sometimes a off the cuff remark or a quirky comment from you unsettles them & you'll see the true person for who he/she is.
always apply the once bitten twice shy principle when dealing with so called new friends, your deadliest enemies are the ones closest to you & not your rivals. your training at your previous work should have given you a good judgement of character, if you die die have to make an assessment, the most important test is the loyalty test. from your posts, you sound like you have insight or experience working with intel officers so you should know their mindset of testing & trust. no need for me to say anymore.