The way I create a work-life balance is to think of my life as a book, with different chapters, and the overall "balance" happens when you look at the entire book. Each chapter does not have to be a forced 50-50% work-life balance. Sometimes it is 80-20%; other times it is 20-80%.
So, I had a chapter when I was in college and a young professional in my first "real" job, and worked many, many hours. My focus was work at 90%.
Then, I had a chapter where I became a mom, and slowly my work-life balance shifted to closer to 50-50%; sometimes it was 10% job and 90% "life"...
Anyways, you get the idea! I was so overwhelmed with trying (read: forcing) to make my life "balanced" that I wasn't happy no matter what I was doing. By giving my family my undivided attention when I'm with them (not thinking about work!!) and giving my work undivided attention (hee hee) when I'm at work helps me to feel more "purposeful" and "in the moment", which is how I define "balance".