In my personal experience working with the oneirogens I've found that they do increase the vividness and intensity of my dreams and for that very reason they decrease my ability to become lucid because I am more engaged in the content of the dreams. They also do wonders for dream recall.
As for specific medicines:
Calea - Quite effective, probably the best one for lucid dream work because the effects aren't quite as intense as the other oneirogens I've used. Best way to consume is to extract with water or alcohol, evaporate to a resin, and encapsulate for oral dosing, I found around 3-5 grams was a good amount for me, or you can just smoalk the leaves.
Silene Capensis - The most effective dream medicine I have used. Highly recommended. I could not get the root ground fine enough to make the foaming method work but 150mg in water each moarning was extremely effective. Takes about 3 days to start working and takes approximately as long to wear off as you have been taking it (if you take it every day for 2 weeks it will be about 2 weeks after stopping use that the effects wear off completely).
Caapi - Nightly caapi doses make my dreams moar vivid and add a specific ayahuasca-vision character to them. I experience tryptamine like visuals in the hypnagogic states between waking and sleeping as well from this nightly caapi dosing regimen. I've also noticed a strong mood-lift and antidepressant effect in my waking life.
Salvia - I have limited experience with salvia alone for dreaming but smoking in the evening did seem to have some effects on my dreamstate, I think this one might also be a good candidate for lucid dreaming.
Mugwort - This is reported to have strong effect on dreaming to the point that even just keeping some next to your pillow will effect your dreams, I haven't worked much with this one but it does seem promising.
Chamomile - Not a lot of effect on dreams but a great bedtime relaxant that seems to help get a deeper moar restful nights sleep.
Valarian Root - A medicine with strong sedative effects giving a very deep sleep that in my experience makes it harder to recall my dreams.
As for lucid dreaming:
There are many techniques available, a bit of googling will turn up all sorts of websites and forums dedicated to these practices. Diligent practice of these techniques is the best way to achieve lucid dreams.
Cannabis is very well known for its effect on dreaming, which is basically making it impossible to remember your dreams. If you are not a heavy user this can be used to your advantage however by combining it with other techniques.
A few methods I've found helpful:
Follow the wake back to bed technique, upon waking smoalk a small amount of cannabis to clear the previous dreams. Then take a oneirogen like calea or silene and go back to bed using meditation/visualization techniques to consciously enter the dream state.
My personal favorite bedtime blend is caapi/calea/salvia leaf smoalked approximately 30 mins before bed with a nice cup of chamomile tea and a dose of oral harmalas.