Start by picking a subject you're familiar with and one that's dear to your heart. Your first article might be about a hobby that you've enjoyed since childhood. It's so much easier to write about something you have a passion for.
There are loads of writing groups on Facebook that you can join for support and encouragement.
Don't write about anything that bores you as you'll only succeed in boring the reader too!
Set yourself a weekly challenge and scour the Internet for ideas and information.You'll soon find you build up a substantial database which you can refer to for forthcoming articles.