Ask any piano mover how to move a piano upstairs, and they'll all give you the same advice: don't do it. Even an upright piano weighs four or five hundred pounds, and when you move one up a flight of stairs, you risk damage to the piano and movers alike. If you absolutely can't afford professional movers, get several people to help you and take things very slowly.
Evaluate the piano's path. Make sure the stairway is wide enough to accommodate the piano with a person on either side of it. See if there are any tight turns. Prop open doors you'll be passing through.
Prepare the piano for moving. Remove or secure the music rack and key cover. Lay out a plastic sheet, and put a blanket on top of that. Move the piano onto this setup and wrap it up in the blanket and plastic. Secure this with a strap. The blanket doesn't need to cover the piano; it just needs to protect the part of the piano that will be touching the stairs. If the piano is a grand, remove the legs and turn it on its side before moving it.
If possible, construct wooden skids on the stairs for the piano to go up. This will create a smooth uphill path for the piano rather than series of right angles, which will be much easier to move.
Move the piano to the base of the stairs. Position one of your helpers a few steps up. Lift the front of the piano, using a strap, and have the helper on the stairs hold it in the air. Put two or three more of your helpers at the bottom of the piano. Have them pick up the other end.
Once the piano is fully in the air, start moving it slowly. Have one of the helpers at the bottom of the piano get underneath it and, supporting it with hands and shoulders, push up with her legs. Move one step at a time, taking rests often. One person should be in charge of leading the move and calling a command for each step.
If there is a landing, you may have to negotiate a turn. If it's a tight turn, you'll probably have to turn the piano on its end to make the turn. As the piano comes to the top of the flight of stairs, have the helper on top lift the piano as it's pushed until it's standing vertically. Take a rest, then maneuver the piano around the turn and continue up the rest of the stairs in the same way.
Do not move a piano upstairs unless you really know what you are doing. It could result in the destruction of your piano or a fatal injury.