When you're planning your writing, always remember:
The context is what requires you to write a specific kind of text, aimed at a particular audience in order to achieve a certain purpose. Each text type or genre has its own particular features, called 'genre conventions'. You will need to make sure that you include these features.
The audience is who you are writing for. This may be teenagers, adults or children. It will help your planning if you can imaginatively 'put yourself in your audience's place' - so for example, if you are writing a letter informing people about a trip, it is likely that they will want to know about cost and key facts such as times and places. If you’re writing for adults this doesn't necessarily mean you have to use long or complicated words - just ensure your writing is clear, sensible and interesting.
This is what you want to achieve by writing the text. Persuasive texts often encourage readers to accept a point of view, buy something, or give to charity. These need a combination of informative, and persuasive (often emotive) language. A text meant purely for entertainment will generally be more light-hearted but all texts have a primary need to engage the reader’s attention.