There are several types of passes but for the most part you can put passes into one of four categories. 

1. Under Passes
2. Over Passes
3. Through Passes
4. Outside Passes

What are some examples of each?

1. Under Passes –  Double Under Pass, Gracie Guard Pass
2. Over Passes – Leg Lace Pass, Smash Pass
3. Through Passes – Baseball Slide, Knee Slice
4. Outside Passes – Toreando

So how do we defend against each?

1. Under Passes – Transition
2. Over Passes – Frame
3. Through Passes – Half Granby, Invert, Far Leg
4. Outside Passes – Frame – Same Side

Which is based? 

• Honestly they are all good you just need to use the right retention skill for the correct pass.

What other factors do I need to worry about?

Timing! Timing! Timing!

1. Timing is key. You have to start these as soon as you know that they are passing. You also have to wait at certain times to make sure it has a maximum benefit. An example would be framing on a Baseball Slide pass. You have to wait until their leg has passed your bottom leg so you can escape your leg. Time them on their transition.
2. Make sure you are structurally sound with frames. 
3. On Half Granbys make sure you are escaping your hips enough and swinging your legs wide
4. On Far Leg retention stay connected with them and not over reaching your far leg
5. On Inverted make sure you are not staying too close, let them bind you up

https://youtu.be/GDB13GVZchI
Tips
Learn ranges

From disengaged open guard

• Keep elbow and knee tight
• Recompose with your opposite leg
• Lift your feet up with your hands in front
• Don’t let your hips get turned create a frame on your leg with your arm and the mat
• Don’t put your far foot on the mat

Knee cut

• Don’t let one leg get between
• Leg lasso and pull out leg
• Keep arm under the knee cut leg

Stack

• Drop the hips down
• Keep your feet moving