So, the reason Lutfij was asking about your hardware is to give more specific information that would be directly helpful.
In a very general sense:
XMP is an OC of the RAM and often built into the motherboard software.
Use a monitoring program like CPU-Z for instance to monitor voltage while under a load. Say, run a benchmark while watching to see what the stock parameters run for core voltage. Then, you can attempt a "quick and dirty" OC by setting at or near that voltage, generally at or near the boost clock of your CPU, and adjust from there based on stability and heat production.
Afterburner is a convenient tool for OC of a GPU.
Make sure your system is clean of dust and dirt, fans are clean. Make sure you have a case with good ventilation. Make sure you have a quality PSU that can deliver the expected load of the combined OC's. Also take consideration of the quality of your motherboard and it's VRM/power delivery and cooling aspects.
And no, overclocking isn't "safe". There are inherent risks involved that could result in damage to equipment. Much of the CPU made within the last couple of gen Intel and 2xxx-5xxx AMD are basically often not worth the trouble due to the really good stock boost clocks and parameters.