1. Las reglas de pronunciación

2. When a word ends with a vowel a, e, i, o, u or the consonants n or s, the stress goes on the next to the last syllable.
For example:
el calendario
los jugadores

3. When a word ends with a consonant that is NOT n or s, the stress goes on the last syllable.
For example:
el reloj
feliz

4. When a word has an accent, ignore all other rules
When a word has an accent, ignore all other rules. Just put the stress on the accented syllable.
For example:
el lápiz
simpático
el fútbol americano