I ask this question because I just want to get a view on what this subreddit views as the dominant technique. I know different things will work for different people.

For me, I practised ADA for about a month with no real benefits. Then I started mindfulness and have had vivid, long, and much more lucid dreams.  

Well, maybe becuz the sign that was pretty off. It was cars smashing into each other, non stop.  

That's awesome haha...  So you would say that they are equally beneficial?  

I have only really tried ADA, but it does have benefits - paying more attention to sensory inputs when awake allows for much quicker stabilisation of a dream by basically focusing on ADA when you become lucid, and forcing your brain to provide sensations from all the extremities you direct your attention to.

I didn't find it helped me to actually get lucid in the first place though.  

I recommend the mindfulness sources that come from the (at least somewhat) spiritual traditions.   You take what makes sense and can skip the stuff that doesn't.   I've seen at least one "scientific" mindfulness book and found it dry and seemingly without basis.  It was trying really hard to find nothing spiritual about mindfulness, almost going to contortions (IMO) to avoid it, and it seemed just artificial and totally without merit to me.   I'm not a Buddhist but can appreciate their traditions.   I would think that even the "non-spiritual" would find value in their writings because they're very much focused on the individual working to form their own transformation.

I like "Mindfulness In Plain English," "Wherever You Go, There You Are: Mindfulness Meditation In Everyday Life" (I think these would mostly satisfy your request).  I also really like Andrew Holecek's "Dream Yoga: Illuminating Your Life Through Lucid Dreaming and the Tibetan Yogas of Sleep," particularly because it connects directly with lucid dreaming.   But it may have too much Buddhism for you.   I think it's still worth a read, filtering out that stuff if you like, this book is chock full of really important revelations about mindfulness and lucidity.  (As is "The Tibetan Yogas of Dream and Sleep".   There are several passages there that are transformational.)

edit: fundamentally, mindfulness is learning to pay attention to yourself and your experiences.    Through meditation (seated or otherwise) practices you strive to exist with a still mind, so that the inner chatter fades away, so you can see clearly to the truth of your experiences, and can choose your reactions/behavior, rather than being ruled by your reactions.

My LDing practice catch-phrase is "Pay attention, reflect, recall."  Pay attention to all life experiences (waking or dreaming), reflect upon them (while you're having the experience and later when recalling them), and practice recalling them: recall your day's experiences in the evening, and recall your dream experiences in the morning after waking.   So it's a holistic approach that involves a constant type of behavior, rather than trying to live one way during the day and another way at night.     Build your own practice around what works for you, as long as it includes these fundamental principles.  

Wow! How do you use mindfulness to do so? What do you do?  

ADA is completely useless. Mindfulness works to some degree. Both are not very effective methods as far as lucid dream induction technique goes. You can achieve much more frequent LDs via other more direct methods, and in contrary to common belief, ADA/mindfulness has NO lasting effect. With reduced level of intentions to lucid dreaming their effect will diminish very quickly over time. They are also much harder to maintain over long period of time (I'm just saying this on behalf of average users). In all, the effort you have to spend to make these methods to "somewhat" work is very high, while the result will always be lacking. As for increasing vividness of dreams, I don't know if it can be proven. Even if it actually does, same result can be more easily achieved via dream journaling or cartography.

IMO, a beginner is much better served to go with combinations of WBTB and other more direct methods such as FILD, MILD, DELD (Michael Radguda's Indirect Methods are even more superior) or SSILD.  

Meaning -- it's not a do it once and works for the rest of your life kind of magic, as commonly perceived by users. If you develop this kind of practice into a lifestyle then it's probably a different story, but even then it's way too much effort as a mean to trigger frequent lucid dreams. Besides, keeping intentions on a fixed subject for a prolonged period is always difficult, generally speaking.  

Well mindfulness isn't just beneficial for lucid dreams! There is so many more benefits  

2 practises of both would be of most benefit!