Should I tin both pins?
You can tin pins at least from the beginning but with some practice you will find that it is not needed.
Sometimes it makes sense only to add extra flux on the pin. Sometimes nothing extra is needed (the flux in the tin is enough). It all depends how clean the pins/wires are. The more oxidized or dirty they are the more likely you need to add flux or even tin.
If you would solder enameled wire on a part which cannot withstand a lot of heat then you should tin the enameled wire (i.e. burn the enamel on the wire) with high temperature setting and later solder the wire with smaller temperature.
I solder enameled wire on the tip of the thick pin of MX switch without tinning pin or the wire. I just make one loop of the enameled wire around he top of the pin, add some flux, put more solder on the iron and make the connection. Temperature around 350 - 400 °C.
I often tin the switch pin which is connected to the diode. In this case the iron temperature is low (around 250 °C). There is no need to add additional flux. The flux in the tin is enough.
I never tin pins or the PCB (nor I add flux) when soldering through hole components to a PCB. The flux in the tin is plenty enough. Here it is important to add tin to the pin (not to the iron tip). But I tin wire (which are composed from more thin wires) ends before soldering them to a PCB. There are a lot of videos on youtube how to solder components to a PCB.
One typically needs to add more flux on the pin when using high iron temperature because the flux in the tin on the iron will burn off quickly.
Again, do not use very thin iron tips nor conical tips. Bevel or chisel tip for everything. You need a good heat transfer.