I started cruising about 15 years ago with my late wife and still love it. Welcome to the club!

I don't think a repositioning cruise is what you want. You're basically looking for a hotel with good food that moves with you. Many cruises are like that. I'd start by asking yourself two basic questions:

1. What part of the world do you want to see? (This is related to the season when you go. Ships visit different regions at different seasons. That's why repositioning cruises exist.)
2. Do you think you'd prefer a mega-ship (4,000 passengers, plus or minus) with all sorts of facilities, casinos to rock climbing walls and water slides, and Broadway-style entertainment nightly? Or are you leaning toward something smaller, say 700-900 passengers, with a quieter atmosphere and a more intimate feel?

Then, if you know (or know of) a travel agent who focuses on individual leisure travel, talk to him/her, Cruise lines depend on TAs for most of their bookings. They pay good commissions and offer their best fares. As posted above, TAs often pass some of this along in the form of shipboard credits or direct discounts. A good one will also have sailed on several lines and will be able to offer meaningful suggestions. You can also get a lot of useful information from YouTube videos. Watching people tour ships with their video camera running may help you decide your ship size preference.

My travel companions and I have never found drink packages worth it, but that has a lot to do with our habits and the lines we cruise on (which offer free wine and basic mixed drinks). YMMV. Once you pick a cruise, look at the packages and pick one that works for you (or none). We've also never gone in for specialty restaurants, but we might this year. The need for one depends a lot on what other options your ship has, The cost of drinks and dining isn't a big enough deal to determine which cruise you want.

Ditto for Internet: pick a cruise first, then look at your choices. I use my cell phone as a wi-fi hotspot while in port or near land, which makes ship wi-fi unnecessary; see if that's possible with your phone plan in the region where you'll sail. In general, focus on the big picture and work out the details after. Don't let the tail wag the dog.

You'll have to choose a cabin type. I don't like interior cabins, though they're inexpensive and might be fine if you'll just use them for sleeping. I've also found suites too expensive; I'd rather spend the money taking another cruise or flying to/from in greater comfort. That leaves outside and balcony cabins, One decision factor is the weather you expect where you'll go. However, another advantage of a balcony is that it gives you a full-wall window. I had a balcony cabin on an Antarctica expedition. Never sat on it to bask in the "balmy" weather (daily highs were around 30°F/-1C), but the view was priceless,

Finally, don't dismiss cruise-operated shore excursions out of hand. Some offer good value for money and might show you things you wouldn't see on your own. At least look at what's available. If nothing else, the process might give you some ideas. And, if your booking comes with substantial shipboard credits, this might be a good way to use them up!