What is the best way to prepare a saturated KCl $($aq$)$ solution?

Add KCl solid to the water till all KCl are dissolved. Then boil off some water, the resulting solution will be a saturated solution when it cools down to the room temperature

Add excess of KCl to water till some solid remains undissolved at the bottom of the beaker. Then raise the temperature to let more dissolved, then cool the solution to the room temperature. If some solid remain undissolved, then the clear solution will be a saturated solution

Add excess of KCl to water till some solid remains undissolved at the bottom of the beaker. The clear solution will be a saturated solution

Add KCl solid to the water till all KCl are just dissolved. The resulting solution will be a saturated solution