One reason for plagiarism is poor time management. You need to plan your time effectively to allow time to research, plan, write and review your assignments.
Another reason for poor referencing is poor note taking skills. You need to develop a system of recording where you find information and also differentiating between direct quotes and your own summary. You can find helpful advice on Palgrave Study Skill website https://he.palgrave.com/studentstudyskills/page/Making-Notes/
Improve your academic writing skills
If you struggle with any aspects of writing your assignments think about using the Writing Cafe (located on the 4th floor of Babbage open 1-4pm weekdays term time) or the help guides developed by Learning Development.
Reference Management Systems
Reference Management Systems are really useful at helping you to organise and store your research - by using the cite whilst you write feature you can also ensure that all your in text citations are included in your reference list.