One of the cards I've done many times is Birds of Paradise. Here are some of them paired with their test sketches I've made for each one.
This version is winter themed:
Another winter themed version that I rejected and was left unfinished.
A Nouveau version:
The following two were painted on promo foils from M11:
This one was made for an altered card contest from Mtgsalvation.com. The contest's challenge was to paint a card inspired by a song, which in my case was Bird of Paradise by Snowy White. It finally won the first place :). This is the said contest http://forums.mtgsalvation.com/showthread.php?t=475538.
The reference photo I used:
And this the song by Snowy White that inspired the card: