I try to be available to my students as much as possible and to let them know we are in this together.  Moving a course from F2F to online is very challenging especially when the students are at different learing levels.  Try to make the students who are not as strong know that you are available to them and you will help them succeed as long as they also put the work into the course (learning).  

Make the course as interactive as you can and have the students participate with their knowledge.  See one, do one, teach one.....If they can instruct somebody else what they have put into practice, you know they have learned the material.