The choice of frame for each artwork will vary, especially if your technique leans in a specific direction. Recessed and flush mount frames suit traditional paintings, while contemporary styles are complemented well by float mounts.
Another thing that matters when framing a piece of artwork is the overall visual style. Classical subject matter pairs well with gold-leafed or dark wood frames, while abstract and modern styles look better with plain frames. Old-style paintings benefit from a vintage frame, while contemporary styles require a different approach.
Contemporary styles often use thin borders as their frames to put as much emphasis on the painting as possible. Some prefer off-white or white frames to remove as much attention from the frame as possible.