The Y consonant sound [j], especially at the beginning of a word, is particularly difficult for English learners from Spanish-speaking countries.
The Y consonant sound [j] is best practiced by placing your hands on both sides of your cheeks. Watch how my student practices this by saying the word yield.
There is only a bit of movement at the beginning with the tongue pressing lightly against the roof of your mouth.
But then rest of the movement is in the jaw. When you say the Y sound [j], your cheeks will cave in a bit.
Watch this short video that I recorded for TakeLessons. Then practice pronouncing the Y consonant sound [j] correctly.
When you're ready, practice by repeating along with me the following words from the video.
The more you practice typical American vowel and consonant sounds, the more you will sound like an American English speaker.
Of course, if you ever need accent reduction lessons, I'm available in person at my Eastlake, Chula Vista studio and online via video chat. Contact me directly for more info or visit my TakeLessons page.