Dont blindfold her dude fucking look her in the eyes and say 'look at when i'm hurting you'. Confrontation is a must when dominating, and girl's love it. You could literally write ten thousand words on this haha, and to help you out Im a sadistic Dom. I think one of the main things is that if you're not a sadist, you are going to have to prepare yourself mentally. You are literally going to be hurting someone you like, and regardless of the fact she consents to it, it is going to feel fucking weird, foreign, and you'll probably want a holy water shower afterwards. So think of it as pleasuring her, and you're just acting. You're not being yourself, you're putting on a persona for her pleasure. Also don't lose yourself in the moments. You need to remain highly empathetic and very observant. Subs dont always use their safewords because theyre too deep into sub space. Watch her body language closely, and try to determine whether you're doing is helping her orgasm or hurting her in a non sexual way.
Aside from that, lets talk about setting up pain and pleasure. Don't just jump in the deep end with a full forehand smash right onto her bottom, and dont start of by slapping her across the face. Start with less intense acts of domination such as pulling her hair from behind, choking her lightly (stay away from the windpipe and don't fuck with the arteries on the side of her neck), twisting the nipples lightly is also a great way to start. Once you feel that she's turned on enough, I would probably throw her over your knee and do some light spanking to start of and then progressively work your way to more intense strikes.
If she wants to be degraded, face fucking is going to be your new best friend. You will need a belt, a room with a corner and a submissive who has consented to face fucking for this exercise. Its pretty straight forward. Drag her (remember by drag I dont mean cause her harm, be careful not to hurt her seriously - its about psychological stimulation) into the corner of the room, tighten the belt around her throat and use it keep her still while you fuck her throat. Tell her to wear lots of mascara and lipstick. During the exercise all of that make up is going to get seriously smudged. You can then spit in her face. She might also like getting written on, so if she likes being called a slut or a whore write it on her. Call her names that she agrees to before hand, because theres nothing worse than calling a kitten submissive a whore... it kills the mood like a fucking dodo.
Anyway that should get you started. Face fucking can be dangerous, so go easy until you know what she is comfortable with. You can seriously bruise a sub's throat, or make them vomit... which has happened and although some girls like that I suggest you don't just off the cuff try it out.
Also girls who like degradation from what I know, like getting facials, but definitely raise that before hand and remember to be a gentlemen and drink pineapple juice. Final note, remember LOTS OF COMMUNICATION at the beginning. I have abit of experience with sadism so I don't ask whether my sub is okay unless its an emergency, but I would suggest that if you're unsure, ASK.
Your catch phrases to research are as follows: breath play edge play impact play
Finally, trust, awareness, understanding and affectionate bind a dom to his sub, and vice versa. That is what separates the sub dom relationship from an abusive relationship. Good luck.