You already know a little Spanish: using English-Spanish cognates.

If you have a fairly broad vocabulary in English, you have an immense advantage in learning Spanish vocabulary.  Cognates, or words that share the same etymology (root word) and basic meaning, can make Spanish easier to learn.  

Look at the following sentences and try to guess the meaning of the underlined nouns and adjectives based on your existing knowledge of English:

El objetivo del actor es explorar su carácter.
La literatura norteamericana es difícil.
El profesor de música es inteligente.

Recognizing cognates could double your existing Spanish vocabulary.  Even if the way the word looks on paper throws you off, try saying it out loud, and you may find that you know the word (or its English cognate) after all. 

Spanish has many recognizable linguistic patterns; being aware of these patterns will also increase the size of your vocabulary and make new words easier to remember.  Many words that begin with an "s" in English have a close counterpart, usually preceded by an "e" in Spanish.  Examples include estado (state), escándalo (scandal), escena (scene), estereotipo(stereotype), estratégico (strategic), estampar (to stamp), estéril (sterile), específico (specific), and estúpido (stupid).  Many English words that end in -tion have the ending -ción in Spanish.  These words are almost exact cognates; in most cases, you can guess what these words mean: conversación, educación, imaginación, moderación, organización, and transportación.