What are the dos and don'ts of finding a job in Cuba?

Are you serious? In Cuba you get 25 dollars a month. Who wants jobb for 25? Please where dö you come from?

There are lots of foreigners who are working legally and illegally in Cuba. Most of the Jobs in Cuba are open to Cubans only, but specialized jobs are open to Foreigners. The pay system is difficult to explain. Embassies hire people on cuban salaries but augment them according to their standards. Cubans working in Embassies make a wonderful living and do a great job.
One Frenchman I know, organizes houses and casa particulares for French tourists and he makes a good living doing that. Like everywhere else, if you are innovative, you can live well in Cuba as well. Not all Cubans want to leave the Island and most of my cuban friends, well travelled as they are, are happy to come home.
Cuba is a bit difficult to explain to people and dismissive answers are not helpful, especially in a place where things are constantly in a flux

Priscilla,
As with all things about Cuba, this is also a conundrum.
You must always learn the language of your host country and preferably be fluent in it if you are seeking employment.
For all intended purposes, Cuba's culture is based on western traditions, the basic process of applying for a job and interviews are very similar to those in Europe and the US, but try to keep politics and personal feelings and opinions that are deemed controversial out of said interview.
You can arrange a position with a foreign company functioning in Cuba with the intention or hope of being assigned to one of their establishments there but, this is mostly for upper management and as a foreigner you will probably have to comply with the proper visas required to live in Cuba and other requisites. 
If you seek employment as a Cuban resident or national with a foreign corporation, keep in mind that the government does the accounting for these companies, the company may pay you a salary let's say, a $1000.00 CUC monthly, equivalent to dollar purchasing power, the estate will pay you a small portion in CUC ($50.00-$75.00) and the rest in pesos, which is worth about 20% of your salary in CUC.  Estate and government firms only also pay you in Cuban pesos with a small incentive in CUC.
There are variations to this, you may work for commissions totally in CUC in other fields as small capitalistic ventures and services are proliferating around the country, however, the legality of this is obscure at best and also highly regulated by the government.

@cochinjew

Hello! I am interested in working and living in Cuba. I have been to Cuba 5 times. I have seen the private sector expand. Is it possible for a "casa particular" owner to have foreign employee? I like to wash, clean, organize tourists from my own country.

@Armando Ruiz

Dear Armando!

I am interested in working and living in Cuba. I have been to Cuba 5 times. I have seen the private sector expand. Is it possible for a "casa particular" owner to have foreign employee? I can wash, clean, organize tourists from my own country. I look forward to your reply! Have a nice day with a smile!

Ildiko

Cubans are leaving the island in droves because of the lack of opportunities, there are few to no jobs for foreigners in Cuba  and living in Cuba is way different than being a tourist/visitor.