The first thing you should do is ask yourself: what exactly do I want to accomplish? Am I going for total native fluency (requiring years of work) or do I just want to have a decent grasp of the language so I don't come off as completely ignorant when speaking to a native speaker? Also, what is your time frame for learning this material? Do you have years to work on it or only a few days or weeks before you go on vacation or meet your significant other's relatives?

Step 2: Get A Home Study Course

There's no getting around it: you're going to have to spend some money on some basic educational materials and this one is probably going to be the most expensive AND the most important. I've used Pimsleur, Rocket Spanish, Berlitz, and Rosetta Stone amongst others, and personally I liked Synergy Spanish (see my review at the end) better than any of the others, especially for someone who just needs to get to a basic level of proficiency where they can handle simple day-to-day conversations and transactions, and they only have a few days or weeks to get there: Synergy uses 68 lessons of 10 minutes each so you can complete the whole course in a few days or weeks depending on how much time you can invest, it's only $49, and if you're in a rush nothing will up your Spanish language skills faster.

Step 4: Find a Native Spanish Speaker Who to Talk to

It could be a friend, it could be someone you met through a site such as Friends Abroad, it doesn't matter just so long as you have a native speaker to converse with occasionally. You don't need to do any type of formal lesson, in fact the more casual and colloquial it is, the better.

Step 3: Dictionaries, Thesauruses, and Translators

Personally I like to use http://Wordreference.com for my online Spanish-English dictionary, I used Urban Dictionary to look up spanish slang and curse words (they're better than anybody for this), and I use Babelfish for my translator. You might also want to grab a paper dictionary and a wonderful little book called '501 Spanish Verbs' that has the most commonly used verbs and shows their conjugations, very helpful.

Step 5: Learn at Least ONE New Spanish Word Each Day--You MUST Commit!

Commit to learning at least one new Spanish word per day--this will be HUGE for adding to your vocabulary although it might not seem like it at the time. I like to use a site called Spanish-Word-A-Day who will gladly send you a new word to your RSS feed or to your iGoogle homepage--I know there's other sites that can also email you a new one(s) each day as well. The important thing is to commit to actually doing this, that way if you don't get any other Spanish work done that day then at least you still did SOMETHING if you've done this, and it really doesn't take but a few seconds.

Bonus Step: Watch Telenovelas! (Spanish language soap operas)

One of the best things you can do to improve your Spanish is to sit down for 30-60 minutes each day and watch a Spanish language soap opera, called a telenovela, which will almost always be available if you have cable or satellite. Personally, I find the best thing to do if you have Tivo or something similar is to turn on subtitles (Spanish not English) and then after a character says something pause it EACH time and figure out what they said, then repeat it a few times to yourself until you've got it and could understand it if you heard it again at full speed, then unpause it and continue to do this. You might only get through 5 minutes worth of the show in 30 minutes, but you will learn a LOT of Spanish.