Direito Civil
Core concepts
Start with the LINDB: vacatio legis, continuity of law and the reduction of the burden of proof issues in the Civil Code. Study the natural person, capacity, absence, presumed death and personality rights (image, name, privacy). In the juristic act, know the defects: error, dolo, coercion, estado de perigo, lesao and fraude contra credores, and the difference between nullity (art. 166, public interest) and voidability (art. 171, private interest, subject to ratification). Prescription and decadencia follow arts. 189, 207 and 445.
Obligations: solidariedade, arras, clausula penal, obligations of giving and doing. Contracts: objective good faith (arts. 113 and 422), social function (art. 421) and excessive onerousness (art. 478). Civil liability: subjective (arts. 186 and 927), objective (art. 927, sole paragraph), risk and excludentes. Also possession, usucapiao, family (EC 66) and succession.
Traps
The usual trap is to start prescription at the moment of knowledge rather than at the violation of the right. Another is to treat a simulated act as voidable: simulation is nullity (art. 167), not a mere defect. Be careful with apparent authority and good faith of third parties.
Rule of thumb
Name the defect, then check the consequence. Worked example: a contract signed under estado de perigo, where one party exploits the other's necessity, is voidable within four years, not void.