I recommend not lowering the bike, its ok to be on your toes unless you plan to just park with your passenger and make vrroooom sounds inside the garage then sure lower it. Other than that dont sacrifice your bike's handling to support a passenger. its all the same when you get going.
mounting - have your passenger mount from the left side of your bike at all times. With your left foot firmly set, have your passenger mount smoothly using the riders left peg with her left foot and and slowly sit on the chair by "SLOWLY" swinging her right leg over the bike. If they do this too fast it may catch you off guard and end up dropping your bike.
education - educate your passenger that in order to turn, the bike leans from side to side so make they do not panic if it leans. In a lean it is better that the passenger keeps a center of gravity meaning her spine should be level with the tires at all times. Unless they are an experienced rider then their instinct will shift weight with you in a turn which is OK, educate the passenger where the pegs are and to watch out for the exhaust.
Riding - if comfort allows it, the passenger should not hold on/wrap around their arms to your waist (on sportbikes. HARLEYS OK
) they should rather hold on to your tank to allow the rider free movement
Passenger hand position on tank:
Other than that, cruise around the block so you get use to added weight and never accelerate too fast.