There is only one way to quickly get to 99 (as in not taking years) and is cast high alchemy. You must have a lot of money now, so go to the Grand Exchange and buy nature runes and high alch an item. My suggestion would plate bodies Mithril (at the time I wrote this guide, Mithril plate bodies were the best item to alch high. However, the price changes all the time, so you can ask someone you see high alching what is the best item to high alch is).
Place the item you are alching high on the same location as the high alchemy spell is on the spell book (for example: if the high alchemy spell is on the third row and fourth column, place the item you are alching in high the third row and fourth column of your bag and runescape gold in the game. Since the spell book and inventory do not match exactly, but make sure you can click on the fate of alchemy high, then the point without moving your mouse).This way, you do not need to pay much attention to your screen and can read a book ordo something else while clicking.
Look at your screen from time to time to make sure nothing happened. When you finish high alching all your items, go buy some more. Continue until you are out of money. You must have a high level of magic now (assuming you had a lot of money to begin with) so you can either return to Fist of Guthix, or go back to making money. When you have more money, you can start high alching again. Anyway, you will eventually reach 99 Magic.
When your opponent finds you and starts hitting you, use your bandages to treat. Once you die, you will be transported on the sides to chase your opponent. When you see it, your biggest auto cast spell damage found on him and buy runescape gold in the game. When he dies, you will be returned to the grip of Guthix lobby. Click on the icon of your spell book and select merge. Keep on casting confuse ducks (ducks switch each time you start confusing so that you do not have to wait for it to wear) until you reach level 11 magic.