The perfect ratio of alcohol and gelatin is the key to making jello shots. If you use too much alcohol, it can prevent the gelatin from setting correctly and result in a liquidy mixture. On the other hand, using too little alcohol can result in weak and flavorless shots. Generally, a good rule of thumb is to use 1 cup of boiling hot water for every 1 packet of unflavored gelatin and 1 cup of alcohol. This will result in a balanced, firm jello shot with perfect texture.