Cutting out alcohol can help a lot, and although caffeine can be helpful when used in topical treatments for your hair and scalp, it’s a good idea not to drink too much of it.
Even simple blow drying can stress your hair over time, so it’s a good idea to try to get as much water out of your locks as possible by gently toweling it (patting and squeezing, not rubbing), rather than using a hairdryer for longer than necessary.
If you have very long hair, especially if it’s also dark (which usually means that individual strands are thicker), then the simple weight of it can cause similar problems, especially if it’s weak already.
Try to keep styles loose, consider a short style if you currently have a long one, and vary your style as often as possible so that any stress that it does cause will affect your hair in different ways at different times, giving it more opportunity to recover.