Two lovely resources:
1) start with the wonderful basics of Peace Is Every Step by Buddhist monk Thich Nhat Hahn. Read a suggested mindfulness practice every day like
I breathe in and relax my body I breathe out and I smile I dwell in this present moment This is a wonderful moment
2) participate in the (free!) Peak Mind Challenge with daily 12-minute guided meditation practices.
Why? Meditating or being mindful is not about creating a blank mind. Instead it is about being aware of the present moment. And when you're paying relaxed attention to the present moment (by noticing your breath or your five senses), it's hard to be lost in a spiraling anxiety about the future or depressing rumination on the past. Try it!