1. apply some waxy lube (beeswax is good enough - not needed to minimize friction but prevent wear and act as a light antiseize) on the seatpost - it will prevent clicking, creaking and if it happens that you have alum seatpost and steel frame then there would be the risk of them seizing up and you'll cursing and swearing when that happens. the lube you want put there does not need to work with friction but prevent movement. the static coefficient of friction is considerably greater than with movement and the pressure on the seatpost is not that great. the higher pressure and the higher sliding speed - the lower coefficient of friction for such substances like beeswax. straight paraffin is crap, avoid candle wax.

2. apply a bolt specific lubricant on the bolt thread. it will help the bolt reach a high enough tension without the threads being damaged and it will also prevent corrosion (stress corrosion is a real thing). apply lubricant on the bolt head so that the non-thread friction is lessened - so that the bolt does not give up as the torsional stress is added to the tensional stress.

3. if you don't trust yourself to go by feel (as only the bolt is vulnerable in this case) when tightening bolts and you don't want to risk having the bolt broken then tighten it to no more than 6Nm and if the seatpost slips (have something to mark it, like a zip tie - a few mm above the point where the seatpost enters the frame) then tighten it some more. usually seatpost clamp bolts take 8Nm torque. but it depends on what kind of lubricant is applied and the grade of the material.