Get your act together
Make sure that you have all the equipment, tools, resources, clothes and attitude you need to successfully reach your goal - before you start in on it. Nothing spoils a motivated mood faster than having to drop everything to find a pair of well-hidden tin snips, or getting to the gym and discovering that the skin-tight leotard you borrowed at the last minute from your sister doesn't meet their more conservative shorts-and-shirts-only dress code.
Before embarking on any venture, always make sure that you know what you'll need. Think like a journalist writing a how-to of your particular goal. Envision each step and look around at your mental image - what are you doing, wearing, using, etc. Watch out in particular for those tricky "hidden" steps that can throw your whole schedule off - like getting halfway through a bread recipe for tonight's potluck and finding the instruction, "Now let dough set overnight in a cool, dry place"!