The direct phrase for "I miss you" can depend on the geographic region of the person you are speaking with. In Spain, you are most likely to hear, "te echo de menos". This is pronounced something like "tay ay-choe day maynos". However, if you talking to someone from Latin America, then you will likely hear "te extraño", which is pronounced like "tay ek-stra-nyo". They "ny" sound is like the "ny" in the word "canyon".
Of the two phrases, "te extraño" sounds more emotional and romantic.
Another phrase that is quite similar to "te extraño" is "me haces falta". It is pronounced like, "may ah-ses fawl-tah" This means something like, "I need you", but it expresses a very deep longing.
Finally, you can follow up the above phrases with "te necesito" which is pronounced like "tay neh-say-SEE-toe". This means literally, "I need you".
If you have to choose between using "me haces falta" and "te necesito", it's probably better to use "me haces falta" because "te necesito" sounds a bit needy, whereas "me haces falta" is similar to "I miss you".
And that's all it takes to know how to say "I miss you" in Spanish. Good luck!
