I would pick up a book on breastfeeding or take a class (usually offered for free at your hospital). It seems like it should be the most natural thing in the world, but it really isn't. Especially when its not going well. So educate yourself. There is only so much we can tell you in this kind of forum. I'll just list a few things you want to watch out for.
You do want to avoid "nipple confusion". This is when the baby gets introduced to the bottle nipple too early and develops a preference for the bottle over breast because its easier. So if you do need to supplement with formula in those first few days, learn to syringe/finger feed. But do not let that baby use a bottle nipple the first 10 days after birth.
Breast milk is based on supply and demand. Some women don't struggle at all with milk production. But for those of us who do struggle to get our supply going to adequately nourish the baby, there are lots of pit falls that can ruin your efforts to BF. The worst one is formula supplementing. I could write you three chapter on this topic alone. Try your best not to supplement with formula at all, rather put baby to breast as often as necessary. But this can be very tricky and this is where you really need some professional help. Straight up demand feeding is not going to work for everyone. I for example ended up with a baby who had a week suck, so no amount of demand feeding was going to help us. I had to supplement because she lost more than 10% of her birth weight, was feeding for two hours in a row (which caused her to use more energy feeding than she was getting out of the milk she got. It is critical that you be checking the babies weight in all this. Don't let people bully you into demand feeding only, there are very real problems that you may have to get through before you can exclusively BF.
The key to formula supplementation in the first few days (if you must resort to it), is to only give them a few milliliters to top them off, I'm talking the tip of your pinky the first few days, and only one 10 ml syringe full after the first week. What you want it for baby to make it at least 2 hours between feedings (cluster feeding in the evening is fine ((thats when the baby eats multiple times in a short time frame, like three feedings in two hours)). A baby who eats every hour thoughout day and night, will burn your out and stress your body to the point that it won't even be able to make milk. You as the mom HAVE to get some rest to be able to make milk. Don't make the mistake I made and suppliment until the baby goes 4 hours without eating. A breast fed baby goes 2-3 hours between feedings and thats what you want to strive for. If thats what baby is doing, you are well on your way to success.
Strive for no less than 8 feedings a day to establish your milk. Do the math, if your baby eats every three hours (which is normal and ideal for a BF baby) thats 8 feeding is 24 hours. If you formula supplement and baby goes 4 hours between feedings, you won't hit 8 feedings a day and therefor won't stimulate your body to make the milk it needs to make. Trust me, 6 or 7 sessions on the breast in 24 hours in the beginning is a death sentence to your milk supply.
Work with a lactation consultant. Your hospital will likely provide you with one, and you will leave the hospital with her contact information. Don't rely on family, friends, or the internet to get you through troubles with BF. You need someone who acctually observes the baby eating and weighs the baby on a hospital grade scale to offer you any advice worth taking. Also, it takes a good 72 hours for any methods you try to start working. When you take everyones advice, you will get contradictory advice, you will switch methods every 24 hours in exasperation and desperation.
When you start to feel you are in trouble, get help. BF problems can escalate very quickly. stay on top of it and get help right away from a lactation consultant.
Don't trust the nurses in the hospital. when it comes to feeding and formula. Keep baby in your room and skip the nursery all together. Some are great, just angles sent by God. But more often than not the nurses in the nursery care more about keeping your baby full, quite and gaining weight than about your ultimate success at exclusively BF. I had a nursery nurse fill my baby to the max with bottled formula against my express wishes. We never recovered from the insuing nipple confusion. I did not succeed at BF my first baby.
Good for you for trying to make this work and educating yourself up front. I have both succeeded and failed in my attempts to BF a baby. I have made a lot of mistakes I don't want others to make.
BF is hard, but here is the truth, formula feeding a baby is hard too. Its all hard. Babies need a lot. But trying to BF when your supply is down is really hard and adding pumping to the mix doubles the work. So only pump if you really need to. Best to put baby to breast if you can.
In summary here some some of the worst mistakes I made:
letting my baby stay in the nursery at the hospital
listening the the nurses about supplementing with formula
letting nurses bully me into thinking my baby was starving
thinking I could do it alone
thinking it was great that my baby slept 4-5 hours in a row (first baby)
thinking I would demand feed my baby no matter what and never supplement at all (second baby who ate every hour and more day and night almost completely burning me into exhaustion)
thinking I didn't have time or energy to make it to see the lactation consultant after I went home from the hospital
Best thing I ever did to succeed at BF
built up a teem of support
mentally prepared myslelf for one difficult road
saw my laceration consultant frequently even though she was half hour away
had husband stay in the hospital with me overnight so WE could feed the baby
learned how to suppliment with syringes not bottle and to only top baby off to get them to go 2-3 hours, not make them full.
Gave up on le leche style demand feed only, because my baby had real problems getting milk out and only an experience lactation consultant was able to see this and help me through it
Trusting my lactation consultant instead of everyone who tried to project their own personal nursing experience on me, including myself (since I had struggled with different issues with my first child that had nothing to do with the issues i struggled with my second baby)