However, mishaps do happen.
Assuming it survived mostly intact - the CRT didn't implode, you could still have a variety of problems. Immediately unplug the set!
If you take it in for service, the estimate you get may make the national debt look like pocket change in comparison. Attempting to repair anything that has been dropped is a very uncertain challenge - and since time is money for a professional, spending an unknown amount of time on a single repair is very risky. There is no harm is getting an estimate (though many shops charge for just agreeing that what you are holding was once - say - a TV, or was it a fishtank?)
This doesn't mean you should not tackle it yourself. There may be nothing wrong or very minor problems that can easily be remedied. The following are likely possibilities:
If you still want to tackle a restoration:
As noted, unplug the TV even if it looks fine. Until you do a thorough internal inspection, there is no telling what may have been knocked out of whack or broken. Electrical parts may be shorting due to a broken circuit board or one that has just popped free. Don't be tempted to apply power even if there are no obvious signs of damage - turning it on may blow something due to a shorting circuit board. If it is a portable, remove the batteries.
Then, inspect the exterior for cracking, chipping, or dents. In addition to identifying cosmetic problems, this will help to locate possible areas to check for internal damage once the covers are removed.
(At this point, most people will assume there is no interior damage and plug the set back in and turn it on. My recommendation is to resist this temptation since as noted, this could result in further damage making the repair more expensive if there are circuit problems. However, if the unit was on at the time of the "incident" or you are really determined to get to the conclusion and would just throw the thing in the trash if it doesn't work or blows up, go for it! But, if you're the more cautious type, continue with the systematic diagnosis and repair procedure that follows.)
Next, remove the cover. Confirm that the main filter capacitors are fully discharged before touching anything. Check for mechanical problems like a bent or deformed brackets, cracked plastic parts, and anything that may have shifted position or jumped from its mountings. Inspect for loose parts or pieces of parts - save them all as some critical magnets, for example, are just glued to the CRT and may have popped off.
Carefully straighten any bent metal parts. Replace parts that were knocked loose, glue and possibly reinforce cracked or broken plastic. Plastics, in particular, are troublesome because most glues - even plastic cement - do not work very well. Using a splint (medical term) or sistering (construction term) to reinforce a broken plastic part is often a good idea. Use multiple layers of Duco Cement or clear windshield sealer and screws (sheetmetal or machine screws may be best depending on the thickness and type of plastic). Wood glue and Epoxy do not work well on plastic. Some brands of superglue, PVC pipe cement, or plastic hobby cement may work depending on the type of plastic.
Inspect for any broken electronic components - these will need to be replaced. Check for blown fuses - the initial impact may have shorted something momentarily which then blew a fuse.
There is always a risk that the initial impact has already fried electronic parts as a result of a momentary short or from broken circuit traces and there will still be problems even after repairing the visible damage and/or replacing the broken components. This is most likely if the set was actually on but most modern TVs have some circuitry energized at all times.
Examine the circuit boards for any visible breaks or cracks. These will be especially likely at the corners where the stress may have been greatest. If you find ANY cracks, no matter how small in the circuit board, you will need to carefully inspect to determine if any circuit traces run across these cracks. If they do, then there are certainly breaks in the circuitry which will need to be repaired. Circuit boards in consumer equipment are almost never more than two layers so repair is possible but if any substantial number of traces are broken, it will take time and patience. Do not just run over them with solder as this will not last. Use a fine tipped low wattage soldering iron and run #22-26 gauge insulated wires between convenient endpoints - these don't need to be directly on either side of the break. Double check each connection after soldering for correct wiring and that there are no shorts before proceeding to the next.
If the circuit board is beyond hope or you do not feel you would be able to repair it in finite time, replacements may be available but their cost is likely to be more than the equipment is worth. Locating a junk unit of the same model to cannibalize for parts may be a more realistic option.
Degauss the set as any impact may magnetize the CRT. Power cycling may work but a manual degaussing is best.
Once all visible damage has been repaired and broken parts have been replaced, power it up and see what happens. Be prepared to pull the plug if there are serious problems (billowing smoke or fireworks would qualify).
If there are obvious problems with color, disconnect (or disable) two of the 3 primary colors with a B/W picture (color control turned all the way down) or solid raster displayed. If the raster is not now a pure color, you have a CRT or CRT purity adjustment problem.
Perform any purity, convergence, or other realignment as needed.
Then proceed to address any remaining problems one at a time.