sure, i have some suggestion
Battle with Riolu. Participating in battles, raids, or gym battles with Riolu on your team will gradually increase its friendship.
Use Soothe Bell item. Equipping a Soothe Bell to Riolu will further accelerate the friendship gain.
Avoid fainting/defeating Riolu. Defeating or letting your Riolu faint in battle will decrease its happiness, so try to avoid that.
Be patient. Evolving Riolu into Lucario requires reaching maximum happiness, which can take some time, even with these methods. Keep up the walking, feeding, and battling, and it should get there eventually.
