Visible Problem is a Killable Problem
Generally speaking there are known problems and unknown problems. Some people say that unknown problems can be also divided into known-unknown problems (the one which we know that exist but we don’t know anything about them yet) and unknown-unknown problems (we don’t know anything about them and we don’t even expect that they exist) 
Good thing about known problems is that you can solve them, workaround them or at least minimize impact which they have. In short – visible problem is a killable problem. Unknown problems on the other hand are hard to predict (especially unknown-unknown category is nasty) and you can be sure of one thing … Murphy’s law will work … they will show up and kick your ass in the worst possible moment.
So whatever you do, you want to expose as many problems as quickly as you can. Agile methodologies place emphasis on interactions and frequent communication with a client. Check how that can help you with uncovering problems …
1. Daily Scrums – prevent people from going dark. Everyday all team members are reporting what they are working on. It’s easily noticeable if someone has stuck with something. Daily scrums make hiding and struggling secretly with a problem very hard.
2. Short iterations and close cooperation with client – if for some reason you are building something different than client wants it’s better to know about it after a first few iterations than after entire development phase. At the beginning of a project you still have time to do something about it. But when you are after development phase, somewhere in the middle of UAT then your options are significantly limited.
3. Retrospective meetings – team is not as efficient as it can be? There are some bottlenecks? There are tools which are slowing team down? Or maybe you are experiencing communication problems? Retrospective meetings is a chance for entire team to meet and for half an hour stop thinking about deadlines, it’s time to focus on what went well and what went not so well and think what team members can do to make following iterations better.
4. Burndown chart and story board – visual representation of progress makes it easier to identify certain problems. For instance if you see that all of user stories are in ‘QA’ state (check attached picture) then you instantly known that something is wrong – there are not enough testers in the team. And finally burndowns … here you can see if your progress is good enough to meet the deadlines. From the very first iteration you can verify if your estimates where more or less correct. If not you still have a time to manage the situation.