I can't answer your question because there's no real magic formula for levelling - you just kill stuff and quest - but this is bad news for you:
Long story short, a friend gave it to me to clear his debts
Blizzard don't recognise the transfer of accounts, and you can't actually change ownership through the account management page.

If you ever get investigated - and it's only a matter of time when you multibox - you will almost certainly get both of your accounts banned, simply because they're not both in the same name.