Yeah, having a dream journal is a great idea! Just having it there and ready to use to write down absolutely anything you can remember from your dreams will start to make your brain realize that these memories are something you want to remember. Also, a dream journal is traditionally a notebook and paper, but a voice recorder works great too. There is an app called "sleep for android" that starts recording when it hears your voice so you don't even have to move. Movement has a tendency to erase dreams, so whatever you do have your method very near by, and ready to go. There are pens with red led tips on amazon or wherever that make it so you don't have to even turn on the light.

Having a dream journal ready is just the first step though. For one, maybe even with a dream journal you still won't remember your dreams at first, so you may need to do something else to get the ball rolling. Throughout the night you go through various stages of sleep, in some stages you are much more likely to have vivid dreams. If you make yourself wake up with an alarm right after one of these stages(REM) then you will much more likely have a dream fresh in your mind. Everyone's stages are of different lengths, so it may take a little trial and error, and there is lots of help online with fine tuning things, but in general I would say to set an alarm for about 5 hours after you go to bed. Your REM stages get longer as the night goes on, by 5 hours they are pretty long. This is also a good time to try out lucid dream techniques(WILD, WBTB..) as you go back to sleep.

There is more you can do to increase your chances as well. Limit bright lights/screens in the 30min to an hour before bed. Don't eat right before bed. Try to watch yourself fall asleep, just pay attention to how your mind changes. Tell yourself while you are laying in bed that you would like to remember your dreams, but it is OK if you don't, just set your intention.

Once you do start having dreams it is important to go over them. Read them throughout the day, and before bed, look for anything that sticks out as especially interesting to you. Look for patterns or similarities between your dreams. Pay attention to these things in real life when they happen, and get in the habit of doing serious "reality checks" in your daily life where you really try to determine whether or not you are currently dreaming, I know this may seem silly, but you want to take it seriously in real life if you want to take it seriously in your dream life. There are lots of different kinds of reality check ideas online, but it's things like thinking about exactly how you got to the place that you are right now, do you have all your fingers, does text look readable, do light switches work, think about where you are then close your eyes and think about if you are in the same place as before you closed them. There's tons of these, but this comment is getting long.

This just scratches the surface, but is plenty to get started. For in depth material there are some really great lucid dreaming books, Stephen LaBerge is fantastic. The practice of "Dream Yoga"(it is its own thing, not doing what it typically thought of as yoga in dreams) is a fascinating extention of lucid dreaming and there is some really good information out there on this as well. If lucid dreaming is the most incredible entertainment system ever, then dream yoga is the most incredible experiment labratory.