It's just keeping on using fertilizer and watering every day for me, I had to try foreverrrr to get some of my hybrids. I think it took me a week or 2 before I started having luck with blue pansies. For some other ones I just got impatient and bought flowers from people in the TBT Marketplace on here, stupid blue roses won't come in for me!!
Some hybrids are definitely harder than others (as people have said, that blue rose). But I've never really had difficulties besides that.
Say I wanted a pink rose, I'd just do this: (X = white, x = red, o = fertilizer or jacob's ladder)
—-X—-
x—o—x
—-X—-
sometimes I'll even do this: (capital O = fertilizer and o= jacob's ladder)
O—X—-
x—o—-x
—-X—-
I don't know if this is even any different from what you're doing but maybe it'll help haha