1. A computer implemented method for effort estimation of a package based software project, comprising the steps of: identifying, a microprocessor, one or more components from a configuration table to implement at least one of a use case flow or a non functional requirement (NFR) or an interface document or combinations thereof derived using an use case of the software project; sequencing, using the microprocessor, the identified one or more components to prioritize execution of the use case of the software project, wherein sequencing the identified one or more components further comprises: classifying, using the microprocessor, the identified one or more components into one of categories, the categories comprising: need to develop the identified component, no customization required for the identified component, customization required for the identified component, and identified component already developed, and evaluating, using the microprocessor, reuse level of the identified one or more components, wherein the reuse level is evaluated by referring to a list of components developed in previous use cases and identify the components that can be reused for the use case of the software project; and attributing, the microprocessor, complexity of the identified one or more components to determine the effort estimation for execution of the prioritized use case by mapping the identified one or more components to a predefined unit effort guidelines table, wherein the attributing complexity includes using an unit effort table for determining the effort estimation requirement for execution of each component of the prioritized use case.