I've only had a few lab practicals but I've done quite well on all of them. The best thing you can do is pay close attention when you're in lab. The way I do this is by writing down lots of notes, not necessarily because the notes themselves are helpful but because taking my time to make observations ensures that I'm being mindful of what I'm doing and not just rushing through. Diagrams are also quite helpful if you're a visual person, especially for the kind of practical you'll be doing.