Formal:
* ฉันคิดถึงคุณ (chan kit teung khun) - This is the most common and polite way to say "I miss you". It literally translates to "I think of you".
Informal:
* คิดถึงนะ (kit teung na) - This is a more casual and affectionate way to say "I miss you". It literally translates to "Thinking of you".
* คิดถึง (kit teung) - This is a very informal way to say "I miss you", often used between close friends or family. It literally translates to "Thinking of".
You can also add more specificity by adding words like:
* มาก (maak) - very much
* จัง (jang) - so much
* ตลอดเวลา (talaat weela) - all the time
For example:
* ฉันคิดถึงคุณมาก (chan kit teung khun maak) - I miss you very much.
* คิดถึงจัง (kit teung jang) - I miss you so much.
* คิดถึงตลอดเวลา (kit teung talaat weela) - I miss you all the time.
Remember, the best way to say "I miss you" in Thai depends on the situation and your relationship with the person you are talking to.