Instructions
Travel to Slateport City, and speak to the little girl in the contest foyer to gain the Pokeblock case. This item is required to create Pokeblocks. If you wish to enter your Pokemon in a contest, stop at the Lilyport contest hall to get a contest pass.
Collect berries as you travel through the land. They can be collected from berry trees. When the last berry is stripped from a tree, the tree disappears. You can plant new berry trees using the Wailmer Pail, obtained from the Route 104 flower shop. Plant a berry using the pail. It will eventually sprout into a new berry tree.
Check the descriptions of each of the berries you possess. The description will indicate a particular berry's flavor. Go to the Lilycove Contest Hall, and approach the berry blenders. Select the berries to put into the blender. A rotating dial will go around while the blender is in use.
Press the "A" button whenever the dial approaches your mark. The more accurate you are in doing this, the smoother the Pokeblocks created. Pokemon can eat more Pokeblocks if they are smooth.
Review the attributes of the Pokeblock you created. Open your main menu. Select "Bag," "Key item" and "Pokeblock case" to review your Pokeblock.