Did you create a goal and forgot to create funnel?
Did you miss a possible step of funnel?
Are you not sure of paths users will take to compelte the goal?
There is one simple answer to all of these questions in Google Analytics, if you navigate to Conversions >> Goals >> Reverse Goal Path and select the goal in question, this will give you all paths that users have navigated through to complete the goal in question during reporting period.
This report will not only help you in creating your funnel if you are not sure of possible paths, but also it will help you in providing you historical data if you have missed creating funnel.
Although this report does not provide the graphical funnel interface and drop-ofs but is great alternative to look for historical data in absense of funnel.
The example screenshot show above is from Google Analytics Demo account.