Aside from fears and doubts growing from within our mind we must also be vigilant about those trying to enter from outside.
When you are using the Law of Attraction, you are fixing your attention onto something that hasn't happened and for the most part, something that there's no 'rational' reason to expect to happen, at least not in traditional thinking.
Often family and friends will kindly offer 'advice' on your dreams. Be wary, while some advice my be insightful, too often they are just sharing their doubts and fears with you. Lock those out of your mind! Guard your mind from negative influences. "Practical", "reasonable" and especially "realistic" are all words that often hide what is really just doubt. I assure you, no one who has truly broken from the crowd and achieved outstanding success did it by doing what the crowd thought was practical, reasonable or realistic. No, those people set unrealistic goals, unreasonably believed they could achieved them and went ahead without knowing exactly how they would end up accomplishing that goal - something totally 'impractical'.
But when doubt is dressed as 'common sense' it is all too easy to shallow it and allow it to deter you from your goals. However think about this; by definition 'common sense' is the sense that is common to the masses. So if you want to continue to achieve the same results as the masses then please continue to use the same sense that is common for those results. If you want to achieve greater results then you need uncommon sense. Sense that is use by only an enlightened few.
Where do you find uncommon sense? It all around you but for an start try Six Minutes to Success or one of the books recommended on the right. Or just keep on coming back here.