The key to ensuring student success is to continually assess students during the lesson. Checking for understanding is crucial for instructors of any level. In a lesson that includes both reading and writing, there are several different ways to assess students.
First of all, there are two types of assessment. Formative assessment involves assessment during a lesson for the purpose of determining what students know in order to help them learn. Summative assessment occurs after a lesson for the purpose of determining what students have learned.
There are several effective formative assessments teachers can use during reading lessons. You can give each student an individual white board and ask them to write answers to quick questions on the board and hold it up at periodic points during the lesson. This allows you to check comprehension continually and quickly, but in a fun informal way. A similar, high-tech method, is to give kids controllers where they can enter in multiple choice answers which can be displayed as class averages on the screen, or allow the teacher to see where the class is.
For writing, an effective formative assessment technique is to have students write and then read their writing to give comments. You do not need to grade the assignments, but provide feedback that can be used to assess formatively where students are. You can use short writing pieces, even as short as one sentence, to do this.