The best thing I've learned in poetry is to give myself assignments. The favorite question asked of writers seems to be, "Where do you get your ideas?", as if anyone could stumble, trip and fall over an idea and miraculously have a poem spring up from the dirt where they lay.
If only it were that easy.
The short answer – I get my ideas from everywhere. Driving to work, playing with the dogs, reading, listening to music, watching the geese glide in to land on the lake near the house. Poetry is everywhere, lurking in your kitchen cabinets, hiding with the dust bunnies under the bed, crouched in the bottom of the vegetable crisper with the plums and lettuce slime.
The long answer - I work at it. If I'm lucky, I get a line or phrase stuck in my head, write it down, and think on it for a few days OR I decide I want to write a poem on a certain theme. That is much harder, but it's always a great exercise in creativity.
For example I decided I wanted to write a poem about coal bed methane production- the flip side of life in Wyoming. Contrary to what television would have you believe it's not all cowboys and ranchers out here. I started researching and found out all kinds of interesting stuff. One was that ranching (Agriculture and the cowboy way) made up a statistically insignificant proportion of the economy, but drives politics and mentality to a degree far disproportionate to its numbers. I also discovered opposing sides on the impact of coalbed methane on flora and fauna.
Digging deeper, I found a study that said the presence of tire tracks in the habitat of a certain species of shrew will prevent it from crossing over the tracks, limiting its migration and breeding opportunities. Another study talked about how the creation of holding ponds for coalbed methane water increased the density of types of ducks and birds in that area- to the determent of other types of animals. This led me to reading about uses for methane gas, the economic impact, and the dynamics of well drilling. I put all the material I find in a folder marked Poem Research. There it sits and waits for when I find that stuck in the head line that needs fleshing out into a poem.
So far I've written a poem about the shrew, the subdividing of Wyoming, and about alkaline water, from my research. The rest is percolating in my brain and waiting for an opportune moment to become a poem. I have folders on Roman history, engineering, physics, and horse breeds; all triggered by the need to research and develop a poem.
The days where a poem springs forth from my head half formed and needing only a good polish are few and far between, but they seem to come with more frequency if I prime the pump with research.