The best way to improve one's spoken English is to talk with native speakers. Colloquialisms and contractions are abounding in the speech of natives, but are rarely taught in books, or at the most, are briefly skimmed over. By practicing English with native speakers, one picks up on such short forms, idioms and accent particulars that are integral to the language.
The internet can be a wonderful resource for those wishing to practice spoken English with mother-tongue users, as millions of English speakers log on daily and many chat sites offer opportunities to talk for free to anyone around the world. A number of international calling software programs operate via the Internet, instead of phone lines, so that international calls from computer to computer are free, not including the cost of Internet access.
English language movies and/or television shows are another good way to improve spoken English when the opportunity to speak with a native is not available to you. Listening to natives speak, even if only via the television screen, is a beneficial way to learn new idioms and pick up on accent variations. Repeating the lines after the characters can help with fluency of speech and ease of expression, which are generally particularly difficult for non-native speakers. Many movies offer subtitles in various languages; watching a film with subtitles in your native language, while listening to the English version is a good trick to pick up on English phrases that you might not understand.
Many libraries offer recordings of books read aloud, along with public speeches or music recordings in English. If your library does not offer such resources in English, they can easily be ordered online and shipped to you. Listening to such books on tape or other recordings is also a helpful way to learn new vocabulary and to work on your accent. Be sure that the text is read by a native speaker with the accent that you are focusing on (whether American, British, Australian, etc.) to get the most benefit out of the recording. Listening to a book with a story that you are already familiar with may help eliminate confusion over new vocabulary and may help to avoid frustration over a complicated unfamiliar storyline.