Use a mirror and/or cellphone to see the tongue placement for the "l" sound.
Touch the tip of your tongue to the top of your mouth behind your front teeth. Use your voice.
Point the tip of your tongue back. Your lips are slightly opened as you use your voice.
The "l" sound
The "l" sound
The "r" sound
The "r" sound
NOTE: "fl" and "fr" sounds are consonant blends. In blended sounds, you pronounce both letters quickly together in one syllable.