Hi There!
I took the TOEFL in Feb 2015 and scored a 118. Lost two points in speaking because I did a bit of "ummm..". I had slightly more than a month to prepare. Although TOEFL is not really tough, formal preparation IS necessary if you want to score well - it demands discipline and knowing a few useful strategies and peculiarities is helpful.
What I StudiedVideos by Notefull on youtube are really, really helpful. Especially for speaking, they give you an exact idea of what points to talk about and the framework suggested is very good. It is necessary to prepare and deliver a good response in the very short time available. Their strategies for reading and listening are also very good. I recommend doing this first.
Kaplan Toefl Premier has some good strategies and practice. Ensure that you use the audio files provided to practice listening. Do the guide books diligently - practice all passages, read what you get wrong, and really understand it before moving on.
Also, the iBT Practice Tests are helpful. I took 2-3 of those. For TOEFL, it is important to get the timing perfected so take as many tests as you have time for.
Once you do the books, make sure you
revisit the important points from Notefull and the book/your own notes at least once before the exam. That's about it, actually. One-two books and Notefull videos, if done very diligently, suffice for a good score.
Summary of a few strategies -For speaking - In short, keep the notes and speech to:
1. Your stance/topic sentence
2. Point 1, reason 1
3. Point 2, reason 2
4. (optional) concluding sentence
This is very important because you have only a few seconds to prepare and to speak. Don't waste time on irrelevant explanations. Be to the point and keep it to one sentence per point. Keep your notes in the structure above. Don't stutter or do "umm.., ah...". Four clear, uninterrupted sentences are better than 6 sentences of unstructured, jumbled and stuttered response. Keep notes very, very short and abbreviated.
Practice at home with a timer. Try out at least 10-15 topics, spaced across at least 2-3 days (so you get time to improve). Record what you speak and listen to it again! You'll find mistakes you didn't even know you were making.
For reading - read each topic sentence (first sentence of each para) and then move on to questions. Don't waste time reading the whole passage at the beginning. Once you read a question, go back to look for the answer. However, at the start, do try to get a general feel of the mood/intent of the passage. The first and last few sentences usually help with this.
For writing - Keep the structure very clear. Topic paragraph with summary of your position, followed by 3-4 paragraphs, which are each organized as: topic sentence followed by description/explanation.
3-4 points with one example for each is good enough. Ensure that you maintain standard English written communication structure (given above). Don't stray from the topic. Practice typing at home, if you are not used to typing on a keyboard.
For listening - Take notes while you listen. Jot down the important points. If two people are speaking, make two columns and put their respective points in their columns. Again, follow Notefull. These guys have really nailed it.
Final ThoughtsIn the end, your score depends a great deal on your general familiarity with English. This is a function of your entire life till now, and not just a month long test-preparation phase. If you still have a lot of time (read year(s)) before you take the TOEFL, I'd recommend reading as many novels (or other books) in English as you can get your hands on. Reading is fun, and it improves your language skills better than almost anything else. Also consider watching a few English movies/series if it's not your native tongue.
On test day, be calm, don't drink a lot of water before the test and don't second guess yourself. If you think a question was tough, move on. Don't dwell on what you think you might have got wrong.
Hope this helps!
Happy TOEFL!