I carry an XD subcompact in 9mm and I also use the SERPA holster. I have two pieces of advice for you.
First, get a sturdy belt. It doesn't have to be an expensive gun belt; I have a $12 "work belt" from Walmart. It's not pretty, but it works well and it's lasted over a year and a half to date.
Second, grab the hem of your shirt and put it between your sidearm and your body. This is called open carrying, and it is wonderful. As a matter of fact, you aren't a real man (or woman, I don't discriminate) until you open carry.
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Let it begin! I'm a real man, i've never OCed and don't plan too. I know to many LEO's that are friends who don't when off duty and I consider their opinion to be VERY VERY good.