The beauty of grappling is the endless question and answer process that occurs when opponents are locked into battle, therefore there is almost always an answer to each 'problem'.
With that in mind, it is important to at least acknowledge some core concepts as a starting point, this will help you to accelerate your learning and give you the foundations to progress to more optimal positions depending on your objectives. Here we list 5 concepts as a starting point (yes, we know there are always caveats ).
1. Keep your arms in.
This will obviously help to avoid submissions, however the main objective is to ensure you are not having your limbs isolated, which can lead to all sorts of mischief. 
2. Don't end up flat on your back.
When you are put flat on your back you are limited in regard to moving and activating your hips and therefore initiating escapes, generally it is a good idea to orientate to a hip in the beginning of your journey.
3. Don't stick your neck out.
This one is pretty obvious, if you stick your neck out with no concern for connection it will be taken home. The next time you sit up from half guard take notice of your connection or lack of in relation to your head position. This is a quick fix.
4. Establish a connection.
This can take on many forms, a gi grip, wrist control, a frame etc. The important consideration is distance, establish where you want to attack or defend from. Normally the one who controls the connections controls the match. This leads in nicely to our final point below.
5. You are either in or you are out.
As mentioned above managing distance is the key to controlling any bout (this is true of all fighting arts). Next time you are passing guard or 'controlling a position', consider is you are in our out. If you are playing in the middle things will get messy!
