NLP Guide: Identifying Part of Speech Tags using Conditional Random Fields

In the world of Natural Language Processing (NLP), the most basic models are based on Bag of Words. But such models fail to capture the syntactic relations between words. For example, suppose we build a sentiment analyser based on only Bag of Words. Such a model will not be able to capture the difference between "I like you", where "like" is a verb with a positive sentiment, and "I am like you", where "like" is a preposition with a neutral sentiment. So this leaves us with a question -- how do we improve on this Bag of Words technique?