When it comes to L1 and L2 differences in second-language writing, some researchers are not fully convinced that there is a fundamental difference. However, when comparing L1 and L2 writing, many would agree that macro- and micro-level writing characteristics exist and overlap (Eckstein and Ferris 2018). This article identifies some of the consistent differences between L1 and L2 writing in English through a review of existing literature and practical observations from consultants at the Vanderbilt University English Language Center who provide one-to-one writing support for L2 university students at the U.S.-based institution. The L1 and L2 writing differences are presented in three categories: word-level, sentence-level, and global-level. Frequent tendencies and common errors of L2 writers are featured within the categories. To support the transfer of information into practice, the authors also include tips and sample activities for each of the three categories of L1 and L2 writing differences. While much of the information in this article could be transferred across L1 and L2 learning contexts, the tips and activities described have been selected for intermediate to advanced L2 learners in secondary or tertiary academic settings. The main goal is to provide an accessible resource for English-language instructors who are seeking to better understand L1 and L2 writing differences to improve their teaching practice.