Lots of good info already re: range ammo and sd ammo so I'll skip that.
As far as holsters for cc, that depends on HOW you carry the gun. Like most folks, I carry mine inside the waistband (IWB). I prefer an IWB holster that has the "tuckable" feature. This allows one to tuck their shirt tails between the outside of the holster and the inside of the waistband, completely covering the gun while wearing a tucked shirt. I find that I'm wearing my shirts untucked now, but it's still good to have the tuckable feature in case one needs to tuck their shirt tails. It's taken a while, but I'm finally getting away from a lifetime of feeling like I'm not dressed unless my shirt is tucked!
I've got a number of IWB holsters. I can recommend Woolfe Gun Leather (I use the "Lone Wolf-T" for a 1911 Commander) and Side Guard Holsters (I use the "Tuck Clip" to carry a Kahr CW45). I use a "Southern Sidekick" from R. Grizzle to carry a Kel-Tec PF9. LINK LINK LINK
For a small and light gun like the Shield, you make find single clip holster (like the "Tuck Clip") will work for you. Single clip holsters are a little easier to put on. I think single slip holsters w/ the clip offset from the gun (like the "Tuck Clip") make for a thinner package than those that have the clip in line w/ the body of the gun ("Southern Sidekick").
I also use a Remora clip less IWB holster sometimes if I'm beltless, e.g. shorts or sweat pants. Mine is the older variety that's not tuckable. LINK
Crossbreed holsters are well-liked as far as hybrid holsters go (Kydex body w/ leather backing), but I'm more fond of leather.
Whatever holster you get, be sure you get a QUALITY belt designed to carry a holster. Don't spend $60 on a holster and then expect a $15 belt from Wal-Mart to suffice. For casual belts, I like the Wilderness Instructor brand. For leather belts, I've got some from LA Police Gear (they were free w/ an order) and Little Bear Leather (out of business). Most holster makers also make belts.
You'll prolly wait at least 3-6 wks for a quality holster to be made. The maker can tell his lead time if his web site doesn't already list it.
Don't forget to get some cleaning supplies for your gun. Keep it simple and buy something like Break Free CLP or Eezox that can be used to clean, lubricate and protect your gun. Depending on the gun, may also need some gun grease.
Tell us how your gun shoots and include some pics!