I have learned through observation that I should never claim to 'collect' something, particularly related to decorating or I will receive hundreds of gifts in that vein. We have all visited (or been) this home at one time or another, where the owner has decided to carry a theme through several rooms, be it elephants, palm trees, roosters, etc. and soon everyone is giving her another version. Inevitably, the day comes where she is trying to find a place to display elephant #101 and realizing she secretly has come to despise elephants and fears she'll never be able to return from the theme that took over her home.
But this doesn't mean themes are to be totally rejected. As a matter of fact I love small groupings of themed items. Some are more obvious than others, they can be a gruping of wall items or on a shelf. Here is a combo from my home I really like.
I started with the wall pictures and later found the cage. The frame's bark finish and twig candle were added because they reminded me of a bird's nest.
Post a link to your blg so we can see your mini-collections!