Welcome Ryan. We're glad you've joined us here at the best motorized bicycle forum available.
As for modifications, don't do anything until the engine has accrued a couple of hundred miles. This will assure that the rings have seated and you've worked out any bugs. There are several things you can do afterward, from mild to wild but only do one thing at a time.
As for your idle problem it would help us to know what engine/carburetor you have. When asking for advice or help it's always a good idea to tell us what you have so we can offer accurate information. However, if you have a Chinese 2 stroke kit, which is by far the most common, then there are two things you can look at.
First, are you using the clutch correctly? You need to disengage (squeeze the clutch lever) when slowing to below about 10mph or coming to a stop. Keep it disengaged until you pedal back up to speed, above 10mph then release it.
You can also adjust your idle speed. There is an idle speed adjustment screw on the carburetor for that purpose. Screw it in to increase idle RPM and screw it out to decrease idle speed.
Good luck. Hope this helped a little. Have fun and ride safe.
Tom