Jiu-Jitsu is hard, it's even harder when you pick up bad habits and play the game, thinking this is the way it should be played. Jiu-Jitsu is a beautiful art that relies on playing off the bottom, displaying a deep understanding of leverage and angles. It's also inherently flawed in terms of it's cultural approach.
This is probably the most common of the issues that less experienced students have. I'm not sure if it's based on the fact that Jiu-Jitsu is naturally viewed as an off your back art or if it's the fact that students see more advanced practitioners starting there with them.
When I start a round with a less experienced partner, I will start seated or even from a worse position. I'm allowing my partner to play from a more advantageous position in order to allow each of us to work from positions what we need more experience in. This doesn't mean that you should or better yet, that I do this with anyone at my level or higher.
The start of a round is potentially one of the most important aspect of any roll. When I roll with someone more advanced, I play off the kneeling position and advance or stand then advance. I cannot start from an inferior position against my own instructor, I'm stacking the deck in his favor needlessly.
In terms of war and battles, would you rather defend the hill or the valley? Which of the two gives you the natural advantage? If we understand that the hill is a naturally better position to defend and attack from, why are we continually allowing ourselves to take the valley?
This ties into the first. We are in love with fighting off our backs, so when our opponent attempts a sweep, yes we defend, but we don't defend like the floor is lava. When you roll with a wrestler, once their back or hips hit the mat, they do everything in their power to get back up. It's engrained in their DNA to get back off due to the ruleset in which they train in.
With Jiu-Jitsu on the other hand, we often accept the sweep as if there's some sort of gentleman's agreement between us. You sweep, once we get past a certain point, I accept, and now we move into a new phase of the game. In reality, as the person who's being swept, we should be fighting to get back and continue to dominate positionally.
Top positions is and always will be the most dominant half of the battle. If you're competing or rolling off of the traditional ruleset, which is the IBJJF, you're only awarded points once you're on top. The Sweep, The Pass, Knee On Belly, Takedowns, Mount, and Back Mount all require you to get up and maintain a top position.
As the practitioner in the top position, you have gravity, the mat/ground to aid in pins, your weight, and forward pressure on your side. Bottom position has none of these things on their side.
The definition of an empty guard to me is one that doesn't have enough physical connections to your opponent. In any guard outside of the closed guard, absolutely needs three or more points of contact in order to be effective. Most students have a natural inclination early on to grab, but often times the feet don't come into play.
The soles of your feet, in combination with your grips are what make up an effective guard. Four is optimal, three is okay, Anything less is a loosing battle, which needs to be rectified quickly. Spider, Butterfly, Collar Sleeve, De La Riva, Revers DLR, Shin to Shin, and Worm/Lapel Guard all require three or more points of contact.
This allows the guard player to control, sweep, and submit with efficiency.
My Final Thoughts
In the end, do not be a willing participant in your demise. Don't start on your butt. Once on top, stay on top. If someone is trying to sweep or dominate a position, fight for that position. In a battle, only one of you can be comfortable, make sure it's you.