For me, the most important thing has been support. You sound really well informed which is great, but you can never know how it's going to go! Someone said to me that "you're both learning how to do it" (i.e., me and baby), and that's so true! It takes a bit of practice, and I'm so thankful for the midwives, health visitors and local breastfeeding peer supporters who helped me. Are there any local breastfeeding groups/cafes near you? Any local Facebook groups? These can be great too.
I absolutely love breastfeeding, and am fortunate to have been able to feed my daughter for 18 months, and am currently feeding my 4 month old son. It's a breeze now, but both had tongue tie that caused me issues, and took time to diagnose. (Note: NHS waiting times for TT treatment can be hideous). I was very determined, but I still wouldn't have managed to persevere without support!
I feed on demand and can't really think of any tips! My children have totally different personalities, temperaments and ways of feeding. My daughter had colic and would cluster feed like mad in the evening, and sometimes for 45 minutes at a time, then sleep on me (the only way she'd sleep!!). My son is super chilled, so I know he's hungry because it's the only time he ever even slightly whimpers! He's a big lad but feeds quickly and efficiently. I guess you get to know their feeding cues.
In terms of expressing, I think it's advised to not do it for the first few early weeks because your supply is settling, and you don't want to over-stimulate and therefore over-produce. Having said that, sometimes you have to (I had to pump exclusively on once side from 3 -6 weeks due to damage caused by a poor latch), and it can be fine. I believe it only takes 24 hours for supply to adjust. Just make sure the breast is properly drained.
Ooh, it's worth knowing about breastmilk itself! When baby starts feeding, they'll get the foremilk first, which is quite watery. The hindmilk is thicker and more nutritious, so it's worth keeping baby on one side, or starting the next feed on the previous side, to make sure they get the good stuff and are more satiated.
Thinking about it, I could write loads more! But I'm no expert. Have a look at La Leche League, it's a great resource.
Good luck!