well, these tips should help you figure out... ive only scored like 800pts at the most tho
all robots go to the garage (obviously) (top middle)
the ones with the tongues sticking out means theyre hungry, send them to the kitchen. (top left)
the ones with the tears or whatever coming out means that they need to bathe (top rite)
the ones with the Z's tells you to send it to its bedroom (top middle-right)
neutral face, or a face thats different from the rest, tells you to place them outside (top middle-left)
the mop is just for you to clean up so you can get extra points, its not necessary. the only places to use the mops are at the top left and top rite corner, and the bottom left. not only that, you wipe at the areas that the petpets made accidents at (only if you fail to place them in the bathroom in time) i just pass that and place the petpets accordingly. if you cant see their tongue sticking out, the flies around them, or whatever, then make your game screen bigger.
lastly, if itll take you more than a second to decide which petpet to move first, then just move it! but of course, you should try get the petpets with the least time remaining... time management is the key

good luck! (now for me to get better at it)