There are so many tips that I could offer you about picking the right size of tampon, what brands of pads are best, how to deal with the agony each month, etc so I'm going to give you tips that most people probably won't. These are from my person experience so I hope they will be of use to you as well.
Periods in general can be quite a pain in the neck, especially after you have had them for several months. The thing most girls get scared about is talking about periods with males. And I would just like to tell you that there really is nothing to be scared about! Although I didn't tell my dad when I first started, he obviously found out from my mom. But he never brings the subject up unless I'm the one to start the conversation. You don't have to feel uncomfortable about the situation. He is a man and knows what girls get their periods. He probably feels uncomfortable with the situation so the chance of him bringing up the subject is slim to none! Boys your age will probably be very immature about the situation if the subject happens to arise. But the older you get, the more understanding the male population is. I have found this out. I'm going to be a senior in high school and the guys are much more mature about the situation, especially at school. They understanding the moodiness, cramping, etc are offer more support. Of course, this isn't true of all guys, but most it is. Don't be scared to discuss the topic with your friends either. They are often the best support system that a girl can have! If you happen to start your period at school and aren't prepared, more than likely they will have a pad or tampon that you can use and would be more than happy to lend it to you. School faculty are also extremely helpful during these emergency situations, even if it is embarrassing to ask! Just remember that all females were once in that position and know exactly what you are going through.
My advice about pads deals with changing them at school, especially on your heavy days. I personally do not use tampons, so pads are all I really have experience with. When my period is extremely heavy, I use overnight pads because they are thicker and catch more blood. The wings are also a lifesaver to prevent leaking over the edge of the pad, onto your underwear, and eventually through your pants. I also try to go to the bathroom every couple classes just to ensure that I don't leak and create an embarrassing scene for myself. Female teachers tend to be a bit more understanding about letting females use the restroom, so try to ask during those classes.
As I mentioned, I don't have much experience when it comes to tampons. When you are ready to try them, make sure to use a plastic applicator and a light absorbency tampon as they are much easier to insert than other types. There are plenty of instructional videos available on the internet as well as tips and tricks to make the experience the most positive one that it can be. Your mom or other trusted female would also be very helpful when you are first learning to use them. Don't rush using tampons unless you feel a need to. And don't ever feel pressured to start using them. You and your body will know when you are ready to tackle them.
Cramps is something that I sometimes experience as well. There are no real remedies that I have found that truly work. I usually just take some medicine and lay down for awhile. They eventually go away and can be quite difficult to deal with until they do leave. But it is just something you have to deal with. A little chocolate never hurts either
I hope my advice helps you a little! If you have any other questions, I'd be happy to answer them.