Find a language parent: a friend, co-worker, your actual parent, or a language tutor – someone who can speak Spanish very well – and ask them, to help you two hours per week.
Ask the language parent to help you acquire grammar naturally, not with study or using grammar books. Ask the language parent to help you learn by having as much of the lesson in spoken Spanish, with minimal amounts of English to help here and there. With too much help in English, you won't get the comprehensible input that allows the neurons in your brain to form connections.
Doing the whole language parent lesson without any English is best. Act out, draw and move on to other Spanish if you get stuck, just avoid English if you can!
Start at a very basic level. Talk about your shirt, the bow in your hair, the weather, for example.
Do learn as many Spanish words as you can by using Mammoth Memory mnemonics from the Spanish word list and then apply these in your discussions.
Ask your language parent to talk with you using children's story books and as many magazines as you can find.
It doesn't matter what language the magazines or story books are written in, as long as there are lots of pictures for you to refer to.
Take magazines with you that cover things you are interested in, like travel or cooking.
Get your language parent to ask you simple yes or no questions about the pictures in the magazines, and you should ask the language parent simple questions such as "What is this?" "What is she doing?" and "Why is she doing that?"
One of the most powerful ways to acquire the Spanish language is to use children's story books. Again, it doesn't matter what language the story is in, as long as there are lots of pictures telling the story.
The language parent can ask you very simple questions about the story that you can answer yes or no to and, again, you can ask "What's this?" "What's that?" and "Why?" It's not about retelling the story.
Finally, get your language parent to teach, very early on, action words such as eat, drink, jump, sleep, sing and complain.
Get your language parent to familiarise you with 50 to 100 action words per session. This is very important.