Every little girl who loves Dora the Explorer would want to have a birthday made around Dora and her companions.
Dora is originally from Mexico and therefore has some Spanish in her speech.
And so, to incorporate all of "Dora" into the birthday we have to begin with the basics and then proceed from there.
But, to begin making it into the Dora birthday that your daughter would want, we will have to begin with the supplies needed for that purpose as well:

1. Tablecloth: A Dora the Explorer tablecloth should not be too big of a deal to use.
   You obviously need the size that will fit your table, but the reason for this tablecloth is because of the actual character of Dora.
   She would be present in the room with the kids and she will bring every other decoration you will have to together to be Dora-like.
   And of course, it will keep things tidy and will make clean up a breeze.
   
2. Cake and Dishware: Of course you want CAKE! But, have it be a Dora Cake.
   Either with Dora printed on it, or with the colors of her show which include purples, blues and pinks.
   And, the kids will most definitely want to eat the cake.
   So dishware is a must and must be in hand.
   There is the Dora plates available as well as the napkins.
   But, make sure you get forks and spoons to match too.
   
3. Streamers and Balloons: Decorate your room with streamers that will color coordinate with the rest of your room.
   The theme is "Dora" so get some purple streamers, as well as blue or pink.
   Add some balloons to the decor and perhaps have some of them hanging around the room with streamers as well.
   
4. Treats: Besides cake, there is always room for treats.
   Maybe some candy of some sorts, like licorice or star bursts, or a drink perhaps.
   These will be a nice touch to your party and will also need to be able to coordinate with the theme.
   
5. Games: A few ideas to go along with the Dora theme.
   Dora is from Mexico and speaks Spanish.
   Have a few Spanish speaking games to play.
   A second language course is always a good idea and it will have the kids eager to learn the words and make the sounds that are unique to Spanish.
   Perhaps you could make Spanish and English vocabulary cards and have a game of memory.
   Or perhaps have a race to see which team gets the most words correct while you shout out the English or Spanish version of the word.
   The kids will love it.
   

Because Dora teaches adventure as well as Spanish words, it is a birthday that can let the kids have fun as well as learn something productive for their future lives.
They will be rolling with fun and screaming with laughter for sure.