Spanish nouns are either masculine or feminine, with their respective articles. The typical rules you can lean on and the exceptions you should be aware of.
How to form the plural of Spanish nouns. Which nouns are the same in plural as in singular; and which are the nouns only used in plural.
How to use Spanish adjectives in a sentence; what are the comparative structures. Does the adjective come before or after the noun; and how to derive the feminine form from the masculine.
Where to place the emphasis in Spanish words; when do you need to use accent marks in writing.
Conjugation tables of regular verbs. Tenses for verbs ending in "-ar", "-er" and "-ir".
Special conjugation rules for irregular "-ar" verbs, like estar, dar, pensar, probar, jugar and lots of others.
Special conjugation rules for irregular "-er" verbs, like ser, poder, haber, tener, ver, hacer, querer, saber and many more.
Special conjugation rules for irregular "-ir" verbs, like ir, venir, decir, salir, pedir...
A list of special past participles for verbs otherwise conjugated normally, for example abierto (open), escrito (written) or roto (broken).