NO, we cannot predict quakes (yet). Many seismologists and geologists are furiously working on this problem. There are some things that happen before a quake that may be useful. One is that the land starts to slowly creep and this movement can be detected using satellites. When the land does move, tiny fractures form and rare gasses like radon get emitted; these can be detected as well. Sometimes water well levels fall quickly before and during a quake. In short, a wide variety of things are being studied to help us forecast quakes.

The answer is poorly. We know about how the buildup of stress caused by movements of the Earth's geologic plates is what supplies the energy for earthquakes, and we know how rapid that is because we know how fast the plates are moving. We also know that this energy can be released in many small earthquakes or fewer large ones, and we know what kinds of faults give rise to different sizes of quakes. However, individual quakes are triggered when the sticking potential of the rocks is smaller than the amount of energy available, and the sticking potential depends on a lot of things that we can't measure.

Some faults give off signals that they're going to go - radio waves or smaller earthquakes - but I don't believe we've managed to understand what those will be for a given fault, if a fault that sometimes gives warning will always give warning, etc. Some earthquakes catch us by surprise.