streetsweeper said:
I know alot of shit about alot of shit, science in particular, motorbikes, drugs, exercise, so I can just write an article and send it into a magazine? Then what happens?
First of all, before you send anything anywhere,
do your research. Any article you write should be well-researched (that is, if you want to build and maintain a reputation as a quality writer), but another kind of research is just as important. You need to research your market - the publications who could potentially publish your piece. You should be pretty familiar with a newspaper, magazine, website or journal before you send them your stuff. Get to know their focus and what sort of stuff they publish, and what kind of readership they're catering to. The type of advertising featured in a publication usually provides a few clues in terms of readership.

You should also become familiar with the type of language their articles tend to be written in (is it tabloid, businesslike, scientific, literary, etc?).
You'll also need to do your research in terms of who you should be sending stuff to, and in what format. I'd recommend contacting the publication by phone or email to find out who the appropriate editor is, and how you can contact them. If you can, find out the publication's requirements in terms of format, word lengths, etc. For example, will they accept submissions via email, or do they prefer hard copy? Small publications might only have one editor, whereas bigger publications tend to have a number of editors who head up different sections - so try to get in touch with the editor of the section where you think your piece will fit.
Having said all of that, I'd suggest that you don't send complete articles to a publication right off the bat. Send them a letter or email, including a summary / synopsis of the article you'd like them to consider. You could also send them an example of another article you've written, and/or a list of prior publications if you have any. If you don't have any, it could be a good idea to start out by writing stuff for smaller websites, zines, newsletters or small circulation magazines, who may not pay you (although they may offer perks), but who will be glad to have the content. And do some networking to see if your friends or acquaintances can offer any leads in terms of publications you might be able to write for. Writing
gratis is frowned upon by many freelancers, but as Strawberry_lovemuffin pointed out, it can give you a foot in the door, and boost that all-important list of previous publications. Once you have a few publications under your belt, you can begin to negotiate with editors in terms of payment and rights - which is something you should do as part of your approach to the editor (i.e. before your piece is published!). Again, research is key - find out what the going rates are in your particular market. Payment is often negotiated on a per-word basis. Writers' societies and unions can usually offer advice on payment and contracts.