Hi mate , firstly did you put the thermal paste on your CPU properly ? Well clean the surface with some sort of alchohol ? Then apply the right amount of thermal paste ?
Secondly don't be afraid of tightening it properly grow a pair of virtual testicles and tighten that cooler all the way ! ( not being rude by the way mate ) The pressure off the cooler will help spread the paste over your cpu so it's an even layer for the best heat conduction.
Lastly use software such as Prime95 to stress test your CPU and generate maximum heat to cure the thermal paste which will inevitably reduce your temps by about 7 degrees ( information off thermal paste providers )
Hope it helped