I want Improve the RMSE score of my AzureML model for my prject

Hello all So i have this project that i want to improve the score of this project that I'm working on but can't seem to lower it bellow a certain point even with fewer features. I suspect that the problem lies with my cleaning and splitting of the data, i have a basic understanding of AzureML and have set up everything nicely for you to understand the model. Here is the experiment: [login to view URL] I want a RMSE score bellow 9.5 Note: The ultimate goal is for me to learn what i did wrong not only improving the score.