I think just start with small hops along the coast before you make an overnighter. Then go as you feel comfortable with your skills and with the boat. Try NOT to be in areas of heavy cargo traffic / bad weather
when you are tired.
You cannot make your crew prepared but each crew can prepare themselves. Staying fit and not eating too much the day before departure may help. Definitely no alcohol prior to departure. Make sure the crew had good rest and make sure they feel relaxed and safe under your command. It helps if someone onboard can take over, if and when you need rest - basic sailing skills and knowledge of reading shipping
If you are sailing close inshore or a long a shipping
lane, things are more tense. Further offshore
it is easier.
With some of my students I do the following exercise: we depart mid-day and sail beam reach for half of the exercise, then we tack and sail back towards the harbour - I plan this so that we depart and return by day - roughly 24 hours apart with and overnight sail in open water
. Such a test passage
tends to expose all and any regular issues that can be then corrected and addressed. 24 hours are easy to manage and there is some night sailing in it too. If you have time, you can make such a mock offshore passage
with your crew before committing to any further passages.