I usually write “For Housekeeping” and place it on a pillow, or sometimes on the dresser. This makes it clear that the money is for them. If I see the housekeeper with her cart on the floor, I try to say that there is something for her in my room.
Also, if you are there for several days, ask if the same person will be working when you leave. If you wait to tip until the end of your stay, it may be a different person from the one who has been taking care of your room.
Usually, I don’t use housekeeping because I have enough towels. I sort of throw the covers up over the pillows and put my trash in the trash can.
If extra shampoo or lotion is needed, I simply ask housekeeping to bring me a few, or I stop and ask the person at the housekeeping cart when she is on the floor.
I finally came up with a solution that works for all of us. I use the sheet set as normal, but I use two king-size blankets. I fold each blanket lengthwise, overlap them slightly down the center of the bed, and then tuck them in at the foot. Each human has ample blanket that he or she can control, and there is no more tug of war.
To save space and make the pantry more organized, I bought a couple of inexpensive, small, plastic baskets to fit my shelves. Whenever I have a partially full box of snacks, I take the rest from the box and place them in the basket. Saves space and keeps things organized.