De La Riva guard is a form of open guard. Popularised in Jiu-jitsu by Carlson Gracie black belt Ricardo De La Riva in the 1980's.
This can be a very offensive guard that can be used to set up sweeps and submissions.
This is a very effective open guard and used a lot in high level competition.
It's a very useful guard even against bigger opponents as you can keep their weight off you while working to upset their base and sweep passing attempts whether the passer is standing or on their knee's.
DLR is known for it's outside hook BUT it's important to control your opponents heel to prevent him turning his front knee out and disengaging your hook.
Focus on controlling his lead leg with your grip and hook while forcing his other leg back like trying to make him do the splits.
It's important NOT to let your opponent square up to you and remove your front leg hook. Always use your free foot to push his hip and frustrate his base.
Use your grips to control his upper body. Either double sleeve, sleeve and collar or sleeve and heel or collar and heel.
Your grips will also help prevent foot lock attempts on your free foot.
Work on controlling your opponent from here, preventing pass attempts and upsetting his base. Then pick 3 - 4 techniques and drill them without resistance before adding them to your positional sparring.