I successfully used a Vitamix blender with Jake Light though cheaper blenders should help too I think. At least one of these tips should help, in no particular order, though some will make worse so maybe use small portion at first:
SANDWICH TECHNIQUE: Add some water, add powder, add more water, shake. This helps prevent powder sticking to inside top too. Make sure powder never touches the plastic when adding
GRADUAL WATER: Put in shaker half the required water, add all powder, shake, add remaining water, shake. This will allow extra force to be applied to mixture when shaking
GRADUAL POWDER: Add powder gradually to the full amount of water, shaking between adding.
TEMPERATURE: Try different water temperature: cold, room temperature, warm. (Warm will likely clump more)
ELECTRIC HELPER: Use an immersion blender, or other type such as electric Ninja is powerful and convenient
TIME: Let sit overnight in fridge before consuming, to allow dissolve
ANGLES: Turn shaker from every angle when shaking, spinning etc.
EXTRA WATER: Add more water than recommended. Will help dissolve more powder
WHISK: Get a bowl and add powder. Pour in just a small amount water at a time until you get a thick but fine mix like the texture of batter. Using a whisk will help. Then pour that into shaker with water and give it a final stir.
SIEVE POWDER: Use a sieve or shake powder in scoop or knead in packet before adding to water. This will loosen lumps before adding water
SIEVE DRINK: Some shakers have a mesh grill to sieve drink before eating
ACCEPT: Learn to love the bits. Chew on or press with tongue
MANUAL HELPER: Use shaker balls or ice cubes
KEEP SHAKING: Shake as soon as possible after adding powder and keep up vigorously for 30 seconds.
PREMIXED: Jake drink bottle may be coming out in future that is smoother and does not require added water