I'm not sure if the new junior cert is in for science or not. If its not the best way to study is to revise the course and do exam papers as well. Do exam papers and revise notes as you go along. For exam papers any will do really because the past papers are just the past papers really there's not much to say about them unless there's sample ones I can't really remember. Also if the investigation is still in make sure its absolutely perfect and that all your experiments are filled because theres essentially free marks going for those... All of that is how I got an A in junior science though it seems long ago now.
Hope this helps and may the odds be ever in your favour!
I find that the Edco exam papers are the best. I use the revise wise books for science when studying as they are great for explaining definitions and for summarizing the chapters and experiments. I would recommend them.
Canot stress the importance of watching videos on youtube. Not everyone learns by reading long chunks of text!
Could also try this app if you wanted:https://itunes.apple.com/ie/app/quickfire-science/id1175933313?mt=8
But definitely youtube videos. Or record yourself reading over a paragraph on your phone and re-listen to it a few times if you learn better by hearing things.
Also diagrams diagrams diagrams!!!!