All good
advice above. I would add a few points (all of which can be disregarded if you have the cash flow not to worry about such things):
1) As many people in other threads have written, it is very rare for someone to find the perfect boat for them on their first
purchase.
2) It is fairly common, after
buying a boat to "cruise" on, that couples/families get started and quickly decided that cruising is not for them.
3) Boats are not an investment, and will only depreciate, so the
concept of "not getting crushed too badly on resale" is a relative one.
4) Operating costs rise very quickly as boat length increases.
When all these things are taken into account, it may be appropriate for you to consider something relatively smaller to start (and learn) with. Acquisition and operating costs are lower, as are losses on resale. You can always move up later.
Look at a lot of boats. Get on a lot of boats. Consider layout,
storage, and tankage for water,
fuel, waste. Those are the important things for cruising. Read, read, and read some more. Search this forum and others for related threads.
Do make a list of your "must haves" and the "kinda wants". The list is important because it is generally less expensive (in time,
money, and energy) to buy a boat with everything on it that you need, than to retrofit various items onto a boat that doesn't have them. (I'm thinking of things like watermakers,
solar panels,
wind generators, windlasses, etc).
Good luck. You'll find something that works, and looking can be fun.