Birthday parties are unbelievably simple when you start with a theme.
Once you have decided on a theme, which may be the hardest part of all, then the only thing left is to start shopping.
Most of us love to shop, so that should be the fun part.
The only thing that may limit you is your budget.
But here are a few of the items you can find when you go with a theme:

• Tableware--Tablecloths and napkins are the building block of the party.
  Even if no one sees the tablecloth for everything that is loaded on top, it's still better than looking at a bare table or using the same-old, same-old, or digging out the good linen.
  
• Cups, glasses, mugs, or other drinkware and serveware--Next in line is everything that goes on the table.
  Cups can be replaced by coconut shells if you are doing a tropical theme.
  Stemware for something a little nicer, and tumblers with your theme printed on them can be really fun.
  Stir sticks are a necessity, too.
  
• Balloons--Every party needs balloons.
  Balloons can be used for so many things.
  They aren't just for decorating, either.
  You can use them for games, to hide prizes or party favors in them.
  Little children to retired adults can have lots of fun with balloons.
  
• Hanging and table decorations--Door and ceiling hanging decorations add so much.
  Glitter and streamers go with it, too.
  Just plain colors or ones that have your theme cut out of them, or shaped like them are really cute.
  The idea is to use every available space.
  
• Wall and window decorations--Wreaths, cut-outs, or any kind of sign or banner belongs on your walls and windows.
  
• Cards--You have to have cards of some sort.
  Thank you cards, invitations, and the like are a must.
  All your guests will automatically know how to dress based on the theme of the invitation.
  How smart is that? No surprises.
  
• Favors and novelty items--Pencils, stickers, rings, cars, erasers, any kind of little token can be used as a party favor or novelty item for your guests to take home.
  Even grown-ups like to blow bubbles.
  
• Costumes and accessories--Sometimes you can have your guests dress up, or sometimes you can invite someone special who is dressed up to perform something for your guests.
  Costumes are a great way to really get into the swing of things.
  Accessories always make or break the costume.
  Little finishing touches can really add to your costume, like jewelry, or an ax, etc.
  Masks make for tons of fun.
  

The most significant thing to remember is that themed birthday supplies really do much of the thinking for you, and it just knits everything together in a great way.