Strawberry Help needed

I'm in desperate need of help with my strawberry plants.  A few years ago I planted a strawberry plant that has thrived every since.  Unfortunately it produces tiny strawberries.  This year I bought another plant that was supposed to have normal sized strawberries, but those are showing up tiny as well.  I'm guess it's something that I'm doing wrong.  Has anyone ever grown strawberries before, and if so, do you mind sharing tips with me?  I was really excited to have fresh strawberries this summer, free of pesticides.