-Drawing: you will be asked to draw diagrams of fruits, insects..etc. in the exam. Make sure it's in pencil, drawn to the correct size, has definite outlines (no 'sketchy' lines), no shading, no arrow heads when labelling and make sure lines point exactly at the labelled part.
-Comparisons: Make sure the points you use to compare diagrams are visible in the diagrams. Use labels on the diagrams as your guide. And don't compare sizes unless you're given a scale. You can compare numbers shape and proportional sizes.
-Designing an experiment:
*Find the variable which is to be changed (from the question) and mention how you are going to change it (ex: to change temperature, use thermometer-controlled water bath at temperatures 10 to 50 degree Celsius).
*List all variables that you have to keep constant throughout the experiment (ex: room temperature, volume of water, insect species). Make sure there's only one variable for the investigation.
*Mention how long your experiment will last.
*Say how you will measure experiments' results (ex: if you're examining presence of starch, say that the food sample which turns the iodine solution a deeper blue contains more starch)
*Finally: say 'repeat experiment to get more reliable results and minimise error. It's guaranteed to gain you marks.
*If you can, set a control for your experiment. (ex: use boiled enzyme in an experiment to test for enzyme activity)
-Drawing a graph: take care of labels of axes, units, scale, using 'cuts' if needed. Always join points using a ruler unless asked to do otherwise (ex: line of best fit)
-Remember the rule: magnification: drawing/real
-Make sure you know how to test for the presence of water, oxygen, carbon dioxide, starch, reducing sugar, proteins, fats, acid and alkali.
-Look at the experiments in the past papers and make sure you understand them well, as this will help you a lot.
Finally, try answering a couple of exams from the past papers. They're sure to give you a good idea of what to expect, and will certainly boost your confidence
