the key is to be grateful ... then to realize what we will achieve
+1
Being grateful is more important than being positive if you want to achieve something. Basically, you look at what you have first (Do you have a family? Do you have water? Did you eat yesterday? Do you have a job?) and then look at what negative things you don't have or don't miss. You'll become grateful and then realize that you can do what you want.
More important than that is to not have big expectations. Do you know those guys who are like "Oh yes I'll be making billions dude, the new Bill Gates of the town"? This is just a sign of confidence but it doesn't mean anything. Everyone can talk, few can do, most can't accomplish. I think that being grateful pushes you forward to accomplish things because you see what you have done so far and keep focusing on it.
I will give you an example. You want to start your own restaurant. You have the finance and you spoke with some suppliers but still don't know how you're going to market it / create demand. This looks like a barrier but if you learn how to be grateful, you will see that you already have finance and contracts with suppliers, therefore push until you make it.
Either way, you've got nothing to lose and everything to gain by doing so. 
