Once we began a game, we surely want to level up faster. We wish if only we could level to 50 over nights. But we know that is impossible, what we can do is to shorten our time cost on leveling up. To level up faster, we need more SWTOR Credits.
If you haven't played any Bioware games, you should know that their games are all about the story. The quests in their single player games are all narrated and you have several options when answering. Options that change the way you advance in the game. Well they didn't make anything different with Star Wars: The Old Republic. The main line of the quest is very well made and the voice acting is flawless. You can give normal answers, or answers that increase either your Dark or Light side. Your answers will also affect your companions, and their allegiance to you. So do you really want to skip on all of that?
The fact is that when you do the quests normally, you will still progress pretty fast. Mainly because you will get so caught up in the story that you will lose track of time and you will struggle to do as many of them as possible. If you start rushing towards the level cap, you will be missing out on more than half the game. So for now, when there aren't many characters at the level cap, you should enjoy the game. There is much to see and to do. When you want to make another character, then you can try rushing that one. Just know that every class has a different story.
You can rush your toon quite easily. All you have to do is skip the cut scenes from the quests and focus mainly on finishing them and grouping them together. With the help of your companions, finishing any quest will be a breeze. Even some Heroic ones. At the moment, however, it seems that by doing PvP is the fastest way to level up. You get a lot of XP from Warzones, no matter if you win or lose. Not only that, but you also have dailies that also give XP, credits and barter items. But if you spend most of the time in Warzones, you won't see almost anything of the game.
My recommendation would be to first play your favorite character normally. Do quests, group up for Heroic quests, do PvP and also space missions? And when you want to try something completely new, then you can get SWTOR Credits and get it to the level cap fast.