It needs time and talent to learn those. It's hard to learn it on your own, I think that college is the best place where you can became really good in it. But as i sad, it needs time. Of course, there are exceptions. If you are gifted and passionate, learning can be easy, and what's most important, fun to you
Paid or free video tutorials are your friends. Go buy some, they are worth it. And there's always YouTube and Google, read a lot. Start with Photoshop and then Illustrator. And then afterwards, if you're also looking to get into web development, that will be awesome as well.
Is really easy you know. Everything in this world is easy. All it takes is passion. When you love doing what you're doing, it becomes easy. Unaware of times. Like for example watching TV. And then suddenly there's nothing to watch. If you try to watch it, then it'll be hard for you. Time feels longer. And you feel like getting angry. Suddenly you trash talk. And now you know, you favorite show will make you numb to time. And everything else you potato couch. When there's a will, there's a way. When there's passion, the way is easy.
It's not easy, it will take time. As pxgfx suggested you may learn from tutorials, Youtube is a great example, when I was starting I learned a lot from there.
If you have creative thinking and interest t hen its easy, else its very hard to make unique design everytime.
If you have Interest in this field then very easy because Graphic need timing for example Practice make a man perfect. Otherwise very difficult
Quite frankly, there is no definite answer to your question. Its a fully developed discipline, being taught in colleges and universities. Yet mastering in it depends on interest, time, resources, observation and experimentation. You have the right balance of these things, hopefully you will learn Graphic Design & Multimedia.