You might just try to start a thread (such as you just did) asking for help and see who chimes in. Not sure if an entire forum would be that populated, although I could be wrong.
Here's my thoughts: use the flower or portrait setting on your camera (which will give a shorter depth of field, blurring the background), shoot in early morning light (less harsh) preferably on an overcast day (less shadows), take several photos of the same plant at different angles and distances, then pick your best one to submit to the database and delete the rest. In addition to a portrait of the bloom, also step back and snap the entire plant so we can see how it looks in situ.
Edited to add: pay attention to the background and keep it as clean as possible - remove dead sticks and such, focus on the part of the plant with the least amount of damage, if you're lucky, try to catch a pollinator in your shot.
Most important: have fun with it.
