I've been published rather a lot.
It's easy providing you have shots that fit the mags requirements. If you don't, stay in touch and keep sending them updates of new work.
Get the direct email of editor or picture editor, if you can - get them on the phone for a chat.
Simply ask ''Could you find a home for my shots in any upcoming issues?''
Go directly to the mag.
I've been in PhotoPlus about 3 times, EOS Magazine twice, Advanced Photoshop 3 times, HJ - Hairdressers Journal, Salon Business Magazine front cover, Practical Photography several times, Digital Arts...and many more overseas.
All the above UK mags were a case of writing off, getting the editors on the phone and asking if they could give my babies a home