To make any kind of headway as a freelance writer you have to be coming up with ideas and pitching several of them a day. It's no good sending a pitch out when the mood takes you, once in a blue moon. By sending out your pitches regularly to the same magazines you are making an impression on that editor and getting your name known. They know you are not just a one trick pony and that you are a serious writer.
But you want to make the right kind of impression. You don't want to bombard them with article ideas that are so far off the mark they are left wondering if you actually know what magazine they are features editor for! And that takes time, preparation and research.
You have to read back copies of your chosen magazines as well as the latest issue. And don't forget to look at the 'what's coming up next' section so you don't pitch an article idea they are already covering next month. Notice the tone of the articles they do publish. Is it chatty, or more formal - do they use lots of quotes from experts or more case studies from ordinary people?
Writing your pitch in the style of the magazine shows the editor you have bothered to read their magazine and can write in the style they favour. And don't forget to address your pitch to the right person, otherwise there's a risk it will get banded about for weeks before reaching the right person, or, worse case scenario, it just gets deleted. Look in the magazine as there is usually an e-mail address or phone number you can use to find out who the appropriate person to address and how, is.
But the most important thing is to try and make pitching articles a habit not a thing you do when you've got a spare five minutes or so. Regular pitching is your friend! The more wonderful, appropriately pitched article ideas you send out there, the better your chances of a hit.