1) You need to know how to prevent/break away from the clinch. A grappler can use the clinch to stifle your strikes and take you down.
Agree!
In order to be able to do so, you will need to understand each and every single clinch situation. Besides that you will need to understand what function it can perform, you will also need to know:
1. How to prevent if from happening?
2. How to break away when it happens?
3. How to take advantage on it when it happens?
For example, When your opponent tries to grab your wrist, you can
1. move your arm away and don't let him to grab you. This is easy to do. You just keep some distance between his hand and your arm.
2. break it away when he has already grabbed on you. This is also easy to do, you just twist your arm to against his thumb.
3. take advantage on his grabbing and apply your locking skill on him. In order to do this, you will need to be good in joint locking skill.
When your opponent gets you
- an "under hook", he also lets you to get a free "over hook" on him.
- an "over hook", he also lets you to get a free "under hook" on him.
- a "head lock", he also lets you to get a free "under hook" on him.
- a "bear hug", he also lets you to get a free "head lock" on him.
- ...
Do you know how to take advantage on those different "contact points" that your opponent gives you for free?
Since there are a lot of different clinch situations, there are a lot of knowledge and skill you will need to develop. After you have developed those skills, you are already a reasonable "grappler" yourself.