1. Break it down
Apply the adage: less is more - this is definitely true for mobile learning.
When writing content, think about the way your posts will likely be applied: if it's on a tablet, you will find unique behaviours from smartphone usage. The main factor to not forget is to minimise your content down into conveniently digestible chunks. People making use of smartphones and tablets maybe approaching your site content in small chunks, or they might sit down for a couple of hours every time.
Your content should be suitable to work for either of these modes. Consequently lessons should be simple, and prepared into discrete units making sure that learners will make progress in small steps, as opposed to the extensive in-depth chapters you would expect in a textbook.
2. Clear titles
While you split a subject up, give your users a roadmap: make them aware of the reason for each lesson, how it builds from the previous lesson, and the way it may benefit them. So if it's academic material, emphasize which element of the syllabus you're addressing, and what analysis requirements they'll be fulfilling. And in case it's a skill you're teaching, offer a practical demonstration of what your users should be able to gain at each phase.