That's one of the most useful and encouraging things I've ever heard about knitting. I got this advice on Ravelry, after I said I was afraid to try color knitting. Words "Icelandic intarsia" definitely would have sounded like something waaaay too advanced back then. Today, I'm knitting a coat in Icelandic intarsia with 5 colors at the same time and it's not scary at all (though I'm sure that people on the train think differently).
Blog of Hélène Magnusson has been a huge help so far. The post about basics of Icelandic intarsia is like reading about magic. It doesn't make sense the first time you read it, nor does it the second, but when you start knitting and just trust her and do it the way she tells you to, it all works out.
I'm talking about shifts in pattern. Say, you have 2 blocks of grey and 2 blocks of black. Then the pattern shifts and you have 1 grey and 3 black blocks. Or other way, 3 greys and 1 black. I'm sure that if I had to do that on my own, the wrong side of my knitting would have been a mess. But with tips of Hélène, it's VERY neat. I'm not going to explain it here, just read her blog, if you're curious, it's worth it.
But as with everything, once you get over your fear for one thing, another scary tjing replaces it. Look at this crazy intarsia and you'll see what I mean. That's Dayana's work, who in my eyes is an absolute goddess of knitting. :)