Hi Moemoe and Yokama
Good luck on the 26th, and please come back and let us know how you did here!
As Yokama says, 5.5 is not very difficult. Some really good advice, especially about speaking! Don't try to be perfect - just talk!
Listening
In addition, make sure you do some practice Listening tests with a timer. To get Band 6 (forget about 5 or 5.5) you probably only need to get about 24 or 25 questions right out of 40. It's a secret - it depends on each paper and we don't know exactly. Here are some rough calculators:
The important point is that you don't need to get all the questions right. Even 30 right will get you around Band 7. In the listening, there is a lot - A LOT - of time for looking ahead. Use it. Predict what the answer will be before you read. Is it a number? a date? a name?
There is also time to check your answers. Don't bother. My advice is don't change anything. Instead, look ahead at the next section.
The listening gets more difficult as the four sections progress. You should aim to get all of Section 1 and 2 correct, and most of Section 3. If you are good at listening, you will get another 8 or 9 marks in Section 4.
Reading
It's the same for reading. Don't try to answer perfectly. Just attempt everything, and move on quickly. When you are finished all the readings, go back and do the hard questions again. You have less than 90 seconds per question.
In the reading, read the questions first, and do any questions which are summaries or gap-fills first or ordering events/people/ideas first. You can get a very quick understanding of the passage by reading the questions first. Leave what-is-the-main-idea questions until the end - they are a lot of work for only one mark.
Jump around like a bunny. Unless you are a fast reader, there isn't time to read all 2500 words slowly and carefully. Skim, scan, look at headings and subheadings, first sentences, last sentences; look for thesis sentences and main ideas.
Some teachers say you should start at the beginning and read carefully. That's fine, if you have all afternoon and you are reading a newspaper with a nice cup of coffee. This is a reading test. The way you read it is quite different from the way you read a novel or a magazine or an email.
Writing
In the writing, look at some of the many examples of graphs here for Task 1, and spend only 40 minutes on Task 2. In Task 1 have an overall statement
Overall, the biggest group of Internet users are young people, but people over 65 are starting to use it more and more.
Don't quote the question, and don't talk about the X or Y axis. Just talk about the people behind the lines and figures.
English and German?
One teacher who taught us Spanish and French in high school told us that when he was driving across the mountains from France to Spain he would sing Spanish songs, or vice versa.
So make sure you sing something in English on the morning of the IELTS test! Here's Adele (Someone Like You) with lyrics, and here (to confuse you) here's a German band (Fools Garden) with their song Lemon Tree (in English, with lyrics). Maybe it will help!