I'm a speech pathologist and I stutter. What I do with those words is called "easy onset." First I think about what my mouth is doing for those sounds. For example, with an L your tongue is hitting the back of your teeth. The R, your tongue is reaching the back of your mouth. When you prepare to say a word like "license," take a deep breath, start breathing out and when the breath is already moving, gently touch the tip of your tongue to your teeth. It's just speech with a lot of air. You can look up videos on YouTube (usually made by SLP graduate students) by looking up "easy onset" or "light articulatory contact."