Then, and only then, do you CUT them off. Don't pull the leaves off - you'll likely dislodge the roots and often will pull the entire bulb to the surface. You feed them. Compost is good, however liquid feed will get down to the roots quickly at this time of year and if you've been underfeeding this is the choice. You grow them dry in the summer.
Tulips like to dry out in the summer.
I had to irrigate my perennial beds last summer in our drought and the tulips have suffered from it this spring. If you planted them in clay soils, you move them. Tulips don't do well in clay - period. Too much standing water and constantly wet conditions to really grow a good tulip. Sure, if you give them what they want and need, they will strengthen and flower.