I would know main ones. For example in H-NMR, the aromatic protons on the ring usually show up around 7.....aldehydes are around 9-10...etc. For IR, I would also know main peaks such as OH's (3300-3500). C=O (1600-1700).....etc. Also for H-NMR, know that if you have protons that are not coupled and thus would exhibit a singlet, but if are within two bonds of a highly electronegative atom (halide, or oxygen)....then the peak will be shifted further downfield (away from zero). Deshielding is downfield (helpful hint). Hope that helps.