Though my name is spelled "Tselil" in English, phonetically it is closer to
TSLEEL, (one syllable)
where I've used the underline to denote emphasis.
To pronounce it correctly, I recommend the following steps:
Say the word "SLEEL", using only one syllable. It sounds exactly the same as the word "seal" but with an L right after the S.
Replace the "S" sound with the the "צ" sound: "TSLEEL". The "TS" make a single consonant sound together, which is the same as the last consonant in the word "hats".
(Bonus). Try to replace the "L" sounds with the Hebrew "ל" sound. Do this by making the American "L" sound, but with the tip of your tongue touching the top of your mouth at the base of your teeth.