Improving model score apart from gbm and randomforest

I would recommend you to re-iterate the model building life cycle again rather focusing on "XGBoost" only to improve the accuracy of a model. Generate Hypothesis (Which features can impact the target variables). Caution! you should perform this step without looking at the data. Do the parameter tuning using GridSearch although with experience you can do this tuning process manually. Finally, do the prediction for test data set.