Great question — answering as the UphillTech team:
Less modge podge. If it's still sticky then you're likely using too much, simply reduce the amount that you're using. Brush it on with a poster paint brush and spread it out thinly.
Full answer by Aaargh Zombies: https://crafts.stackexchange.com/a/13180 (CC BY-SA 4.0).
Need it done for your business? UphillTech.
