Consider taking the "Bargello Seasons" class on
www.quiltuniversity.com . In that class you'll get instructions for 4 different bargello each of them different and increasing in difficulty, and online help from the teacher for the duration of the course (and a bit after). It was a great way to learn bargello - her instructions are clear and concise, you can post pictures of your color choices and the teacher will look at them and advise.
I took both the "Bargello Seasons" and "Bargello Blues". In Bargello Blues we made a far more complicated bargello for the 1st half of the class, then in the second half we designed our own with teachers assistance. My avatar is a variation of the pattern offered in the 1st half of Bargello Blues.
Sue