Breastfeeding!

This will be my second little one! I tried desperately for my first to latch. It didn't go well (I get really down on myself about it too, I feel like im not trying hard enough or something) so I pumped with her. Then to make matters worse I got nexplanon inserted and it really put a cutback on my milk supply. Soon I wasnt making enough milk for her so I switched her to formula. She was my first and I felt like I didn't know what I was doing. There was a breastfeeding specialist at the hospital when she was born and she tried to help but it wasnt doing much. Now my little girl is 2 and I would really like to breastfeed my 2nd as long as I can. Any suggestions, tips, tricks? Literally anything with help me!