I found that using flashcards was the most helpful way of me learning.
Its the same way when you learn the basic Hiragana, it goes Ka sa ta na ect.. and then when you add the two lines over it, it changes to Ga Za Da Ba.. ect.
I also find it useful instead of learning the basic Hiragana first, and then the extra, Learn them all together.. like study Ka and Ga.
But make flashcards (it also helps you learn out to write them) and it will help you alot!