Less IS more for home decor.

When you're shopping for accessories to complete your decor, it's wise to subscribe to a philosophy of 'less is more'.  What does that mean?  Rather than buying many small items that have no intrinsic value, look for fewer items that provide the impact that you need.  That's not a reason to immediately discard your favorite collection of Swarowski crystal figurines, since collectibles and antiques, have history, a family value, a memory, or other strong reason to have them.  The goal is to avoid cluttering spaces with items that are just 'there' without meaning.   A few high quality items do have more impact than inexpensive 'stuff' you buy just to fill a space.  
That's not to say that you need to switch to minimalist style, although a more spare room will feel open, clean, and certainly be easier to care for. 

How to accomplish 'less is more'?  Use the largest pieces in your room to guide you on what styles and colors work well in the space. It's always a good idea to use a professional interior designer since the time will be well spent.  Do you have a pattern you can draw from? A color that needs to be accented?  How does the overall space feel without accessories?  Small? Large?  In small spaces, fewer, large scale accessories will help keep the space from being crowded. In a large space, larger accessories will be scaled correctly so they won't feel 'lost' in the overall scheme. If you desire a candlestick, get ONE. Make it a large enough in scale to have an effect on your design, rather than a collection of 3 or 4 that get 'lost' since they're too small individually.  Often, the background color of your space will be a guide.  Perhaps that color needs to be changed to make the collectibles you DO have, be more cohesive.

Examine your style. Call a designer or take one of the many style tests available on-line.  Why? If your style is English Country, then a collection of bone china teacups fits with your decor.  The impact of collections is greater when they are grouped together, so a fabulous glass-fronted china cabinet is ideal to showcase such a collection.  Spreading them around will likely make the space seem crowded. If you have many collectibles, and love a cozier space, try switching pieces out seasonally. Have fun weeding out pieces that don't really have meaning to you, and creating new arrangements with pieces you retain.  It's not necessary to have every table, shelf and surface filled with items.  Even if you don't use a room much, except for displaying collections, it's a great idea to allow spaces where the eye can 'rest'. 

For traditional rooms, symmetry is often desired.  Rather than multiple small items on a buffet or mantle, add a pair of larger items (lamps?) and then a few smaller paired items in between.  Arrange them so there is interest in height and shape.  In modern style rooms, spare is desired.  A great piece of art and one table lamp can create a perfect vignette in the corner of your living room. Do away with multiples and small items; store them, weed through them, give them away. Instead of grouping small picture frames on the piano, create an arrangement on the wall with coordinating or matching frames for more dramatic effect.  A grouping of ceramic vases on the windowsill will have more impact than spreading them around on the end tables.

Remember that It only takes a few beautiful or special things in a room to make it memorable and wow-worthy.