For men, "pom" is generally used, even though they use another words on another occasions. And for foreigners (males) using only "pom" has no risk at all.

For women, "di chan" is formally used. But in daily life, Thai women, except the old, like to call themselves by nickname. So you must be careful to notice whether those nicknames mean the third persons or the speakers themselves. Look at this sentence. "Pop mai chawp....." It can be interpreted as "Pop doesn't like......" or "I, called Pop, don't like....."

Another word that should be mentioned here is "chan" which can be used by both sexes. The elders both males and females always use this word when speaking to the youngers, though they use "pom" or "di chan" when speaking to other persons with the same age. In fact, "chan" was commonly used in the old day. But it is not too weird if you still use this word.

Please note that Thai people always omit "pom" or "di chan" when refer to themselves in speaking with others unless it can be misinterpreted by the persons they are talking to.