We had a self defence session when I was in the 6th form (nearly 30 years ago now - gulp!) and I can still remember it...
There were several things that still spring to mind as being important.
The first (which I have rarely come across elsewhere) was to explicitly give people 'permission' to hurt other people when they attack you. It sounds strange when you first hear it - but we (particularly girls!) are so conditioned by society to be nice, not hurt people, to play by the rules and so on, that apparently when people (not just girls) are attacked, they try to fight back 'nicely' and find it difficult to actually start to hurt somebody, even if they are hurting you...
So knowing this in advance is useful, because you will already have thought about it and given yourself permission to really hurt somebody who is attacking you, not just trying to hurt them a little bit so they'll stop attacking you but actually to really hurt and incapacitate them so you can stop being attacked and escape. And if that means 'fighting like a girl' and gouging eyes or pulling hair or whatever it takes rather than turning into some amazing jujitsu ninja that can fight 'properly' and win then that's absolutely fine.
The next was the phrase 'Grab, twist and pull'. Basically if you're attacked and the attacker is a bloke, if you're in a position to grab his nuts then do - but grab, twist and pull to really hurt him and stop him in his tracks. try mentioning this as a tactic when there are any men around and watch them all rapidly cross their legs and wince - and confirm that this would be an effective tactic!
Another was giving yourself time if you are caught in a chokehold with somebody trying to strangle you in their arms. If you can, twist your head around and down and into the angle of the crook of their elbow - it will stop them from being able to crush your windpipe as quickly and give you a chance to breathe again.
Doesn't matter how strong the attacker, they'll still have things that can be hurt. But go for things (in addition to the ones mentioned) like trying to bend back (and break) the little finger rather than the whole hand if somebody is gripping you - much easier to do - and in most cases will cause the person to release their grip. Eyes are vulnerable too - squeezing your fingers and thumb together into a point is strong enough to hurt eyes quite badly when jabbed into them - without using just one or two fingers to gouge at them which are then vulnerable to being hurt themselves. Same finger arrangement also good for jabbing in the kidneys at the back. Oh and stamping on the achilles tendon at the back of the leg/heel is good too if you can - as it will slow them down or stop them from running after you. (not so good if they are wearing boots though).
Sorry just realised this is a bit long. And also writing some of the things has made me wince - the Grab, Twist and Pull, the eye gouging etc - because you do end up thinking I shouldn't be doing that because they could be hurt for a long time or I could damage them permanently - which comes back around to the first point. Yes, you could damage them permanently. But they are the ones attacking you - not the other way around. If they wanted to stay in perfect condition they shouldn't have attacked you. It's perfectly reasonable to do whatever you need to do in order to survive - and your survival certainly comes above their right to remain undamaged!