I would suggest the following topics (forgive me if this is a bit disorganised)

Languages:

    R, Python (pandas, numpy), C++ or Java, Matlab/Octave

Stats & Machine Learning Topics:

    Neural Nets,Decision Trees,SVM,

    Regression (Linear, Nonlinear, Logistic)

    Clustering (K-means, Fuzzy C-means, Mixture Modelling, etc.)

    Time-series Modelling/Prediction (AR, ARMA, ARIMA, Exponential Smoothing)

    Bayesian Techniques

    Statistical Model Development

System experience:

    Linux administration

    Big Data Libraries (hadoop at a minimum, Mahout, Hive, 

Storm, Yarn as well)

    Data cleaning and large scale data management