Planting Bulbs

I planted some a couple years ago when we first moved into this house. They are still coming up each spring.

My question is though, do you plant them in bunches or long rows or just sprinkled here and there and where, around trees or in a place of their own? This is the part I can't figure out, mine don't really look so great I guess.

I saw some bulbs just this weekend and I got that hankering to start planting.