In what season are you getting married? Below is a year of ideas to help you in your planning:

Winter
Holidays: Christmas & New Year's Eve
Popular Colors: Blue, maroon, dark, rich colors

Centerpiece Ideas:
Large snow globes 
Pinecone or evergreen wreath with pillar candle inside 
Ice sculptures 
Decorated Christmas tree 
Favor Ideas:

Miniature snow globes 
Christmas ornaments 
Evergreen-scented candles 
Stuffed Christmas stocking 

Spring
Holidays: Easter & Memorial Day
Popular Colors: Yellows, pinks & pastels

Centerpiece Ideas:
Tulips in watering cans 
Small birdhouses 
Small potted plants 
Decorated Easter or May Day baskets 
Favor ideas:

Small watering cans with a votive candles inside 
Personalized seed packets 
Flower bulbs 
Chocolate Easter bunnies 

Summer
Holidays: Fourth of July
Popular Colors: Sea green, peach, vibrant colors