Walter Pall's blog is a constant source of inspiration for me. His inimitable style and no nonsense advice is just so refreshing.
Walter is in my view the premier bonsai artists in Europe.
His website features pictures and progressions on some amazing bonsai, as well as travel reports, Articles and videos. Luckily Walter post the majority of his blog in English, rather than his native German. I am lucky to be able to speak German, so the fact that some of the articles are only available in German is no problem to me, for anyone who does not speak the language, Google translate does a reasonable job.
Make sure to have a look at his articles about modern growing substrate and his feeding and watering regime