The best way to improve your writing is by doing exercises , there are some free good exercises out there which you can use to improve your writing;
Intro to creative writing: Exercises for Story writers : these are some good exercise that you can use to improve your writings and it has also some exercises about creating characters.
One Two Fiver :One Two Fiver is a series of stretches for warming up your writing muscles.Start with a single word.Type it like you mean it.Now write two words.Move on to five…Keep typing until you are writing. its an easy way that you can use to when you are trying to come up with an idea for your writing, then you can continue writing about that idea.
Story Grid : A question every first time author has is: Where do I begin? Your idea has been expanding within your mind for months, you know who your characters are, your setting, your plot. Now it’s time to put everything into story form. Problem is, you don’t know where in the world to begin.Here’s where to start…. ( taken from suite101.com)
Writing prompts: Do you need an idea or a writing prompt or two to get you going too? If so visit this Imagination Prompt Generator , it will give you starting ideas to begin your writing.
Writing exercises: Here are some writing exercises which you can use to get some ideas
23 Writing Exercises: Here are 23 different writing exercises , they are very useful and interesting, it includes ideas, prompts, resources , and exercises
Writing Forward: This website is really great it has fiction writing exercises, poetry writing exercises, ideas, prompts, resources, news, writing tipsand grammer writing tips , its simply all you need for your writing
96 Resources: Here are 96 resources for fiction writers these include writing workshops, tools, name generators, courses, agents, publishers, author services, copright informations, and many more.