The paper discusses thoroughly a problem of determining tilt over various measurement ranges by measuring Cartesian components of the gravity acceleration with application of accelerometers that are Microelectromechanical Systems (MEMS). The presented standard and original methods are based on various mathematical relationships between the components and the pitch and the roll. Their application results in the fact that the realized measurements are characterized by different sensitivity and accuracy (experimentally evaluated to be of $0.18^{circ}-2^{circ}$ for a tilt sensor built of standard MEMS accelerometers). Each method is discussed in detail with regard to the respective sensitivity and accuracy of the measurement, and its application scope is determined. Essential part of the paper are guidelines for an optimal selection of the number and type of MEMS accelerometers, as well as appropriate mathematical formula, to be used in a specific case of tilt measurement.