Adjusting soil ph

Hi all,

After reading these forums I decided to get a ph meter, and it turns out that my soil has a ph of about 7.2.

I have never messed with ph-ing before, can someone point me in the right direction of how to safely lower the ph? I have some ph down powder for water, can I use that? and should I apply it to the soil and then water with normal ph water, or water with lower than normal ph?

I have looked but can't find any detailed info on how to do this, any help would be appreciated, thanks,.