Dear (noun) = cariño
Dear (adjective) = querido
To = a
Querida berta
querido amigo
Mi querido.
Querido (for a male). Querida (for a female).
mi cariño/a mi querido/a
Bastante bien, cariño.
Querida Señora Rey.
"Estimada Srta. Estrada"
If you are saying "I'm working my dear" as something that is going on right now, you could say "Estoy trabajando, cariña." If you are talking about the future, "I'll be working, my dear", then it would be "Voy a trabajar, cariña" or "Trabajaré, cariña" Just remember that the Spanish "progressive" tense only applies to present action.
Estoy loco por ti querida/o :-) (female/male 'you')
dear dear
Todo cuanto digas cariño mío / amor mío / pastelito / bizcochito / rey / reina / cielo...