Making Contacts
How can you make these contacts? The easiest way is by making yourself available for as many different kinds of assignments as possible. Let's say you write the television column for a technology magazine, but you also have some expertise in computers. It's a simple matter of a phone call to ask your television-column editor whether he can put you in touch with the magazine's computer-column editor so that you can pitch a few story ideas. Do a good job, and you'll have two editors on your side. Learn something about cell phones, and maybe you can pitch that editor, as well, to further expand your contacts within the magazine.
The same idea applies to working with a magazine's marketing and advertising departments, too. Most editors will have no problem with passing along key telephone numbers to you if you tell them that you are looking to land some more work by writing advertorials and marketing materials. You're already a friend of the magazine, after all, so you should be able to help out the other departments while meeting your goals for your own increased income.
Here are a few kinds of other work you can offer to do as a way of networking with various departments at a magazine:
Proofreading
Writing advertorials
Writing custom publishing materials
Writing PowerPoint presentations
Fact checking
Working on advertorials and custom publishing materials (advertising materials that are geared toward a particular interest or consumer group) has a built-in networking benefit, as well. If you're writing an advertorial about one of the magazine's key advertisers, then you will have to work with that advertiser's marketing department to some extent — thus allowing you an opportunity to network with the point people at that company. This gives you a new level of sources through which to work when brainstorming editorial story ideas. You'll likely be in a position to hear about new products and services before any other writers, and thus you can be first to pitch story ideas about those products and services to your editors.
Taking on public relations work for a magazine's advertiser is a good way to earn extra income, but be careful that your writing for the advertiser does not create an editorial conflict of interest. In most cases, you cannot be both a product's promoter and its editorial reviewer. Always keep your relationship with the magazine's editor as your top priority.
And so, while this kind of networking will help you cement your base by being a magazine's go-to writer, it also will help you expand your base to make the magazine's advertisers your clients, too. This is just plain smart, because it gives you additional income while making you even more valuable to the magazine itself.
Think about it from a business perspective. If a magazine's key advertisers respect you as a writer, they're going to say so to your editors, who will often be more likely to give you additional assignments as a result. It's a win-win situation, which is the best kind of business relationship you can have. It's the kind of relationship that not only cements the magazine as one of your repeat clients, it cements you as one of the magazine's go-to contributors.

