Here's a couple of tricks I used when first learning to meditate:
Go in a quiet room, close your eyes and make sure your sitting comfortably.
Breathe really deep, counting to ten inhale, count to five holding it, then count to ten exhale.
Focus solely on your counting and breathing.
once you have gotten past this stage you can try "focus meditating"
where you sit comfortably, and focus on one object in front of you.
Try and think of nothing, just breathe and focus on the object.
I've found candles work quite well, they almost hypnotize me...
As for visualization, I can't really help - it comes naturally to me.