Keep Practicing. Don't expect to be speaking fluent Spanish a couple of weeks. It takes time to become familiar with key sounds, grammatical rules and to also be able to think in another language. However, less can be more with languages. It's better to spend 30 minutes three times a day practicing verbs or learning vocabulary, than one 90 minute session. You need to engage the brain regularly and keep Spanish on the tip of your tongue.
Develop an "ear" for Spanish. Unlike with other languages, there is no excuse for not submerging yourself into the Spanish speaking world. Cities across America have Spanish speaking communities that you can make friends with once you've learned the very basics. Spanish music is also available to listen to on the radio, and you can watch the news in Spanish on the television or Internet. You can't progress to writing sentences without knowing the very basics.
Speak as much as you can. Although reading a book or watching television provides you with an appreciation and understanding of the Spanish language, you must speak it on a regular basis to increase your speed and pronunciation. Spanish has a number of sounds made with the throat that the English language does not have. When you're a baby and learning a language, you make these sounds as part of the learning process, and it's the same when learning another language as an adult. Although you'll look silly, stand in front of a mirror and practice making the core sounds. Also, look at the way Spanish speakers move their tongues and shape their mouths as they speak, and try to replicate this.
Don't give up. You can make huge progress in one week, but then fail to progress much the next week. Progress is not consistent in language learning, so don't get frustrated if you're struggling. Keep working hard and try spending time practicing material you already know well; this can help you make that next step.
Make things interesting. To stay motivated you need to use a variety of different learning techniques. You can make translation flashcards which you can leave it your pocket and read when you're traveling to work or on your lunch break. Alternatively, you can label different parts of your house with relevant words, for example la pared (wall) or la puerta (door). If you can afford to, go on holiday to a Spanish speaking country. You'll be motivated to practie your Spanish before you go, and will also be able to see the results of your hard work, once you're there.