1. First of all, of course, the outline. If you choose mathematical modeling, you can recommend textbooks from schools with good applied mathematics, such as Zhejiang University, Fudan University and Peking University. For example, the mathematical modeling written by Professor Yang Qifan of Zhejiang University can be used. 2. Then, if you have time, you can refer to several blocks in mathematical modeling and read corresponding mathematical books, such as regression analysis, combinatorial optimization, operational research, time series analysis, ordinary differential, partial differential and so on.

3 Find some mathematical modeling problems in previous years and the number of models established by others through what steps.

Generally speaking, the second point depends on the time you put in. If you are not a math major, you'd better not get involved in the second point and find a math partner.

Ps, I almost forgot, programming is necessary, at least learn C, matlab, sas, spss and other mathematical software to use as much as possible.