I've seen people say that without the Tendo's Ranma would have no way of supporting himself. Leaving out the fact that Ranma has lived off of the land before and has actually taken jobs within the manga a few times (worked at a hot spring -right picture above-, as a waitress -left picture above- for both Ukyo and Cologne, and Genma asked Ranma once if he was working at a bath house). Here are some jobs Ranma has the skills for already. Also the Tendo's are not his only option he could stay with others like Ukyo (who he and the Tendo's lived with during the Gambler King story arc) and Kodachi (who he stayed with once in the anime and she had given him his own personal dojo) amongst others.
Magician - using techniques like how in his battle with Mousse he blew himself up, had a half dozen bunny rabbits, a dozen doves, flags, flowers, mini parachutes for all his stuff from his sleeves, his body switching technique to switch places with things(switched with a bear at Miss Hinako's, a log in battle with Herb, a statue to get away from Ryoga, etc.), Using his martial arts to do tricks that appear to be magic like standing/ walking on things that should not be able to support his weight (like Kuno's sword), lifting things that he shouldn't be able to lift (like all those multi-ton boulders he likes to pick up and throw), crawling/walking on the walls and ceilings (he does this very often in the manga), running up vertical objects (like the telephone pole he ran up chasing Cologne), etc.
Ventriloquist - one time he faked Akane's voice to mess with Ryoga, another time he faked Ryoga's voice to mess with Akane and Ryoga, another time faked Kuno's voice to have Kuno apologize to Kodachi.
Puppetry - He uses Kuno as a giant puppet a few times.
Thief - Ranma has attempted to steal stuff fairly often like the water proof soap, tried to steal the Shi Shi Hadoken scroll, wishing sword, etc. He stole food from Ryoga when Ryoga was turned into a kid, stole food from hot spring guy, stole the bowl of food that had the dragon whisker, ect...
Waitress - Done that a few times in the manga for both Cologne and Ukyo.
Cook - Is a very good cook in the manga.
Construction worker - Ranma has shown the ability to do repairs around the Tendo's house in the manga and with his massive physical strength and abilities this would be easy for him.
Professional Sports - Ranma's abilities and competitive attitude would make Ranma very good at sports.
Demolition work - He wouldn't even need equipment.
Model - Ranma's female form at least is shown to be very attractive and Ranma is proud enough in his looks and shameless enough to make a good model.
Circus Performer - high wire no problem, throwing knives no problem, juggling no problem
Protector - Bodyguard, Bouncer, etc.
Spy - Has abilities that would allow him into places he shouldn't be able to get into.
Lifeguard - Swam the Sea of Japan and has demonstrated knowing how to save a drowning person - Miss Hinako and Akane.
Seamstress - We see Ranma sewing in the manga and creating his disguises.
Housekeeper - Ranma is shown cleaning in the manga. Heck he can't stand a mess and starts cleaning it before he thinks about it as seen in Miss Hinako's house while going to steal her fighting fish and cleaning the dojo.
Stunt man - would be excellent at this
Delivery person - With his abilities he could deliver things much faster than conventional methods.
Masseur (when male)/Masseuse (when female) - Ranma has given massages in the manga to Akane to calm her down after he has angered her and offered Nabiki one to pay her back for the ticket he accidentally destroyed.
With his skills, abilities, and talents many other jobs could be done by him. Since he learns fast he could also acquire new skills/build on existing skills as well. For example, he has demonstrated some knowledge in medicine/human biology that could be built upon. Treats his own wounds, basic first aid, some herbal remedies, some pressure points (at least weak spots and most likely the sleep spot which he was going to use on Ryoga after seeing Happosai use it but didn't get the chance and likely knows more), CPR used on Miss Hinako, etc. and could learn more.