Voyage planning starts with an appraisal, which is essentially a feasibility study. This includes looking at obvious details such as water depth, overhead clearances, and the things that affect them such as tide. Many elements of voyage planning come naturally because they meet the standard of common sense: Check fuel, water, provisions, spare filters, safety equipment, and so forth. To determine if you have enough of everything you're going to look at the distances involved. You'll listen to the weather, and consider the effect of current. Now you can calculate ETAs and make an educated guess as to the duration of the voyage, which you will then pad to be on the safe side. You will look at the status of your vessel and its equipment. If something isn't working properly, decide whether or not it is a deal breaker, rather than proceeding on the basis of let's see how it goes.