Obtain many paragraphs of literature in the language in which you want to be fluent. These can be obtained from textbooks, newspapers or books in your second language.
Ask a native speaker to read the paragraphs to you and record his speaking using a computer or device that will allow you to save and replay the recording.
Choose a paragraph with which to begin practicing. Play your recording, listening only to the first sentence of the paragraph. Listen to the sentence several times.
Read the sentence aloud to yourself three or more times until you can say it smoothly.
Put the written paragraph away and recite the sentence from memory several more times, focusing on fluency.
Repeat these steps, practicing sentence by sentence, until you've made it through the whole paragraph.
Listen to the recording of the native speaker reading the whole paragraph.
Read through the whole paragraph as many times as necessary until you are saying each word smoothly and without stumbling.
Continue practicing this method with other paragraphs on a regular basis.