Like others have said, if you have ideas of what you might want to do just imagine yourself trying one thing out, but when considering any roadblocks don't think about them too much or consider them to rule out that path, as there could be many factors that could rid you of those roadblocks, I guess it depends how big and impossible you consider them to be, but it's also a good thing to get advice from others (ideally the combination of friends, family and strangers is a good mix imo) and sometimes it might be good to actually TRY OUT a path for yourself and if it doesn't work out, you can (usually) go back to where you started and try another path, but by saying "(usually)" it would depend on the complexity on that path and what it involves, who it affects etc., so generally it's best to get advice on specifics
