Because 90% of the cards I have ordered are themed, I'm never short of inspiration, but what I DO struggle with is peoples choice of colours. I was asked recently to do deep cream with bright scarlet, and to me, it looked atrocious. It was a wedding bookatrix, and they loved it, but the 2 colours didn't go together at all. It's a good job we all have different tastes, because I wouldn't have recommended those colours to anyone!
I love doing kiddies cards, the "louder" they are, and the more twinkle and sparklies the better, just up my street!!