Sentimental Analysis on Twitter Data
You should look at literature on unsupervised sentiment analysis. The paper by Peter Turney could be a good starting point.
Thumbs Up or Thumbs Down? Semantic Orientation Applied to Unsupervised Classification of Reviews Turner 2002

You can also check this if you use R https://datascienceplus.com/unsupervised-learning-and-text-mining-of-emotion-terms-using-r/