Find or create a wire base. Use wire cutters to cut a long piece of sturdy wire to the length and height you want the arch to be. You can also purchase a balloon arch kit from the store, and use the wire frame from there.
Because wire gets flimsier the longer you cut it, this method is best used for smaller arches.
Anchor the arch. Stick the ends of the arch into a bucket filled with gravel, pebbles, or sand. If you bought a pre-made arch from the store, it may already have a flat, base or platform. In this case, place something heavy, such as a brick or cinderblock on the base to weigh it down.
Add a thin layer of colored sand or pebbles to your bucket. This will hide the plain sand or pebbles.
Wrap bricks or cinderblocks in paper that matches your balloons. You can also paint them to match the base of your balloon arch.
Blow up four balloons with a balloon pump. They can all be the same color, or they can be different ones. Tie the tail end of each balloon into a knot as soon as you finish blowing it up. Try to make each balloon the same size.
Use a regular pump for this method, not a helium tank.
You don't have to use a balloon pump for this, but your lungs may get tired after a while.
Tie two balloons together by the tails in a double-knot. If you are having trouble with this, you can tie the balloons together using string instead. Repeat this step for the remaining two balloons. You should now have two balloon pairs.
Twist the balloon pairs together to make a clover shape. Place your first set of balloons over the second one in a cross shape. Pull the bottom two balloons upward. Pull the left one to the right, and the right one to the left. You will have something that looks like a four-leaf clover.
Alternatively, you can tie the balloons together in a cross shape with some string.
Tie or twist the balloons to your wire. Pull the balloon clover against the wire. Make sure that the wire is resting against the knot in the middle of the clover. Twist the two adjacent balloons together so that they close in front of the wire.
You can also secure the balloons to the wire with string or colorful ribbon.
Repeat the process to make more rows. Blow four balloons at a time. Twist them into sets, then twist the sets together to make a clover. Slide the clover onto the wire, just above the bottom row of balloons, and secure it. Keep doing this until the wire is filled.
You can use all the same color or you can alternate colors.
Stagger the balloons. Let the balloons in row two rest in the cracks between the balloons in row one.
Picture source: Pinterest