Here are some tips from our experience as first time visitors. We were looking for waterfront bungalows not hotel style accommodation. Had searched trip advisor reviews closely. Narrowed down to Tara Beach Resort, Hideaway Island or Paradise Cove. Chose the latter (read my review specifically about this place) and very happy. Location was everything we wanted. Great to stay at resort some days, but day trips away easily arranged (whilst it is a bit out of town it's not a huge distance). We had ideas of what we wanted to do but no firm plans. Better that way to accommodate any changing needs or your availability. Overnight to Tanna to see volcano is a must (we did daytime trip but night would be better). You can only take 5kg luggage with you so have to still have a room on mainland for the night also. This is one trip you need to plan early then work everything else around it as they don't fly every day - min of 4, max of 6). Note cruise ship days and plan for activities away from Port Vila or stay in your resort those days (prices increase in Port Vila). Look for local operators to support - you might get a pleasant surprise. Don't expect luxury in buses - open the windows and enjoy the experience. Some advised us to hire a car to take ourselves around the island but we took a local operator round island tour and feel we learnt and discovered so much more than if we had been on our own. We were fortunate that we were the only people on the tour that day. Alternatively you can hire a private driver for the day (same price as round island trip for 2 - our hosts could have arranged this for us) if you want to be sure of a private guide. Get advice from locals/resort staff re what you should pay for transport and negotiate the fee before you get in.
Rather than just visit the Mele Cascades we chose the abseiling tour - great way to experience it from a different perspective. Hike up is quite challenging but view is fantastic. No issues for beginners - you will be looked after well and it really isn't scary. Other resort guests recommended the Lelepa Island Day Tour so we decided to try this at the last minute. Really glad we did it. Taken to two beautiful snorkeling locations and it was quite a relaxing day. Well looked after and much to see and learn about from the local guides. You will visit the local village - don't be afraid to strike up a conversation with the locals. Might want to watch the weather for this trip though - it was overcast at times for us, occasional showers and was a bit rugged getting back. Started to get rather cool. Wouldn't want the weather to be any worse than that. There's no real accommodation over there but I understand it is possible to stay at a "guest house" in the village. That would be an experience. Alternatively you could camp on the beach - there are toilets and fresh water at one location (a real Survivor experience). I believe Lelepa Day Tours is also a good option for fishing - not for big game, just smaller stuff - but much more economical.
We learnt a lot by doing the tours. Certainly have a better understanding of the place for a return visit in the future - enough to be a little more adventurous in our planning next time. I'd consider going to Santo and would definitely be looking at the more secluded locations. We were very tempted to do a scenic flight over volcanos which included a stopover at Epi Island and swim with dugongs (but my underwater camera died). Would seriously consider trying to get to Epi Island in future.
We had an afternoon flight and wanted to spend the morning in Port Vila. Dilemma was what to do with our luggage. Our accommodation hosts arranged for us to leave our bags at Bay Watch restaurant. We looked around Port Vila, returned there for lunch then caught a bus to airport. That worked really well.
I hate the city so a couple of hours in Port Vila was enough for me. Next time I will look for more snorkeling locations but not disappointed in any way with how our first visit turned out. Felt we got a great introduction to the place.