Hi Dave,
If you want to reply to certain posts just press the quote button and that post will appear in your reply box and own post.
Good things I always find are the shortcuts at the top of the page such as "Subscribed Threads" which is under Quick Links which are threads you have posted in and it's easy to check if there's been any new posts as they will be highlighted in darker, bold blue and another easy way is to just click on "New Posts".
Enjoy it mate, cheers :w