Find a Spanish language course online. Among the many free sites are Study Spanish and Spanish Progams. Most of these sites are split into educational levels. The user can start at the beginning or pick up Spanish at an advanced point. The drawback is the user must learn at his own pace.
Watch a Spanish language channel an hour or so a day and try to identify words with actions. There are different levels for this too. PBS has programs for beginning Spanish speakers, and there are two all-Spanish speaking networks and an HBO channel. Use the dictionary to identify unfamiliar words.
Spend time around native speakers in person. Ask questions (in English) when you must, but listen and learn.
Take an accelerated language learning program. Rosetta Stone and Rocket Language Learning are two such programs. Both cost more than $100, but are designed to teach the user the language in a short time.