The following guidelines should be followed whenever writing. Look up a dictionary to check unfamiliar words. Talk to family members or friends about the topic. If necessary, do some research at the library. It is almost impossible even for a native speaker to write finished copy without notes.
Notes can be as simple as a list of words, a graph or even a picture.
Don't worry about spelling or grammar at this stage. Just jot down anything that comes to mind. You can always delete it later. This plan is very important, so spend time on it. At this stage, you need not worry about spelling and grammar.