I wrote this on an earlier thread, hope it helps:
How to prepare for skill tests:
1. Memorise how to write a detailed and flawless experimental method. Every single detail. People lose marks for some of the most trivial things (numbered steps for method, independent and dependent variables, a proper aim + hypothesis).
2. Know reliability, accuracy and validity like the back of your hand. Always remember what makes experiments reliable, accurate and valid. Learn how to assess whether experiments are reliable, valid, accurate.
3. Learn how to present data, especially everything about graphs. Know which graph is suitable for the data, lines of best fit, independent variable on x-axis, dependent variable on y axis.
4. READ THE STIMULUS CAREFULLY. It’s a skills test, so a majority of the content and its context will be given to you. This makes it crucial to study and understand the stimulus before you attempt the questions in the test.
5. Have a good understanding of the content. Yes, this is a skills test, but that does not mean completely rejecting the content. Do not go into too much depth, but ensure that you have an overview of the content. For example, for module 7, it is crucial to know what pathogens are, however you do not need to study the lines of defence against pathogens in detail as long as you have the general idea.
6. Practice questions. If you have a textbook with skills related questions, attempt them, and compare your answer to sample responses.