I am keenly aware that this entire situation the world is enveloped in cannot be helped. It is a side effect of a raging pandemic that the entire world has had to adjust their life to. I am aware of this. I do not begrudge this. But I find it increasingly hard upon a certain division of majors: science. Science is best taught, and traditionally is so, in a lecture hall because the material tends to be so heavy. Discussion is limited, lectures are heavy, and memorization is very essential in succeeding. And it is for this reason that science classes have found it so difficult to transition online. 
Take labs for example; where previously one would write a report on an experiment that would be performed, now students are given sample data and instructed to write a report. Now, believe me, it is rare for any student to actually know the mechanics behind a lab when the lab is being performed, the understanding traditionally comes later while writing the report, but now it is even harder for students (or me, at least) to garner what the hell is actually going on. We become sort of robotic in our learning, where we are not actually learning, but just completing the requirements necessary for the class grade. 
Another such example is homework. With the transition to online, homework in most science classes has become graded. It is too easy to get lost in the pattern of looking answers up and simply inputting the right ones, since we are all so focused on getting the assignments done rather than actually learning anything at all. And homework is very essential in creating success in science classes. One does not truly learn the material and master the concepts until they have done it, by hand, themselves. 
I don’t know the solution to these problems, and I cannot deny that some of these issues can’t be helped (they almost seem inevitable when accounting for the nature of online classes). I can only make suggestions as a science student myself. 
My first suggestion is to strictly follow the routine you would in any in-person class. Wake up for class, try to get out of bed (because as someone who spent their first week of online classes attending lectures in bed, I am all-too-familiar with the addicting feel of a blanket that lull you to sleep, especially if it’s 8 a.m. in the morning), and actually listen to the lecture. My first two lectures that I attended, I am ashamed to admit I spent the majority of scrolling through Instagram or swiping through Tinder. And so, whenever a Zoom class or a Blackboard web conference is in session, I always make it now a point to keep my phone in another room, far away from me, so as to avoid any temptation. Don’t be too hard on yourself. With people isolated as they are, the Internet happens to be the biggest connection we have to the outside world, and so it is very tempting, but focus on classes. 
My second suggestion is to read the textbook. The key to being successful in science classes, material-heavy as they are, is to read the textbook. I did this in the in-person instruction anyway, which leads to my other suggestion: follow the study routine as you would normally. It is essential when accounting for the changes in science classes. 
Science classes are tricky when it comes to the online interface, and unlike other classes, are detrimental if not taken seriously. For many intro-level classes, learning the material is key to building a solid foundation. Therefore, it is important to maintain your routine and follow the material as you would normally. Hang in there my fellow science majors, we’ve got this.