I killed a Revered Dragon at Level 59 and was hoping that I'd meet a Legendary Dragon earlier than suggested too. After killing loads of Revered Dragons and amassing over 60 Dragon Bones in a chest I realised it wasn't going to happen. Eventually I reached Level 78 and visited Lost Tongue Overlook and there he was, my Legendary Dragon waiting for his ass whooping!!! Legendary Dragons are grey in colour. I was so sick of Revered Dragons that I was sneaking up and seeing they were Red and fast travelling before they kicked off. People who meet a Legendary Dragon before Level 78 are very lucky as mine appeared exactly as people had said. I didn't use any glitches, just leveled up my skills. Below are some quests that will reward you very well and take away some of the boredom on your way to Level 78.
I found some quests that offer multiple skill levelling as a reward so I thought I'd share the information with you all.
'Retrieve Finn's Lute' quest for Inge Six Fingers who can be found in the Bard's College in Solitude. The mission is super quick and easy requiring you to visit Stony Creek Cave at the very east of the map and collect it from inside a chest. The cave is really small and you will find a skill book in there on a table along with a Stone of Barenziah if you're collecting those too. Return to Inge six fingers and she will reward you with a full skill point increase for each of the following skills: Light Armour, Alchemy, Sneak, Lockpicking, Pickpocket and Speech.
'Find Pantea's Flute' quest. Pantea Ateia is also in the Bard's College in Solitude. This quest takes you to Hob's Fall Cave which takes a little while to fight through in order to collect the Flute. The rewards for completing her quest are skill increases in the following: Alteration, Illusion, Enchanting, Conjuration, Destruction and Restoration.
'Retrieve Amulet' for Shahvee quest. You can find Shahvee at the Argonian Assemblage outside Windhelm. Pick up the quest, visit the place marked on your map (Random Location), collect the amulet and return it to be rewarded with the following skill upgrades: Light Armour and Lockpicking.
Angi's Camp: Archery Game. If your archery skill needs increasing then head over to Angi's Camp which is located south of Falkreath at the bottom of the map. Speak to her and she will allow you to attempt her archery challenge. You will need to speak to her after each round to begin the next or retry. Each completed round rewards the challenger with levels towards the archery skill and you will gain her special bow at the end. This challenge is worth 6 full skill levels to the archery skill if completed.
A really nice boost I think you'll agree.
There are loads of quests that offer a single skill upgrade as a reward too although the ones I've mentioned give the most upgrades. There are some other double rewards for different weapon types but they all easily reach Level 100 with normal adventuring. Don't forget that everytime you level up you can buy 5 levels of training for skills which really helps. There are 90 skill books to be found in Skyrim which also give you a big boost.
I hope these tips help those people like me who didn't use a glitch and enjoy the game.