You can take some small diameter wire (like bell wire) and temporarily place it in the idle air bleeds to partially restrict them and go for a test ride. If it improves it is an indication your idle jet is too small. You will then need to determine what size the idle jet (IFR) is in the metering block and enlarge it. Be careful. A small increase in diameter makes a big difference in the amount of fuel it will pass. Go up .002 at a time and test. When you get it close you can fine tune with the idle air bleed size if the are removable.
A wide band O2 meter takes the guess work out of this process.