I went solo last November. It was a great trip! I felt so accomplished and proud of myself after. It was my first trip anywhere solo so I was still a bit uneasy about being alone in a family oriented place. I recommend a few things that were reassuring to me when I felt overwhelmed -
1. Stay at as nice a resort as you can afford. As a solo I got everything done sooner and taking breaks at the resort and enjoying the pool/balcony was a great way to break it up so you feel busier and not lonely walking around all day long, so a resort with more to do is helpful. If I go solo again I will def be doing AKL! But EP area resorts are great too because you can walk. I always found that the buses made me feel the most alone because there was no stimulation and I had no one to chat with.
2.
MVMCP - SO much to take in and do/see, no one will even notice you are alone. Same goes for the Osbourne lights and storytellers in Epcot.
3. Eat at restos with lounges or bars to sit at. At Jiko and Cali Grill I think you even overlook the chefs. Also eating during off peak hours will make you feel less subconscious since fewer people are around. Resort counter service meals can easily be taken to your room/balcony if you find yourself not enjoying eating alone. (I only felt strange at O'hana, but if you do, pull out your camera and browse. You will forget about people around you!).
4. Another note about resorts - the convention resorts will tend to have more and be more familiar with solos since they are frequented by business travelers. YC, CR, CSR and I believe the Dolphin have convention centers.
5. Single rider lines are amazing. I also recommend doing shows during the busy hours, and any rides such as Pirates or small world where a bench to yourself may feel awkward, during very early or very late hours when the crowds are lower. I think when people (and CM's) saw me solo they just assumed my family/friends were in bed and I stayed out later!
6. It is much easier to find seats and viewing spots as a solo. I went during Wine and Dine weekend so it was busy, but maybe not as much as peak Christmas. But I still think this holds. There is much less of a need to get a seat early and sit there by yourself without entertainment.
7. Dining with an imagineer - It is a lunch at the Brown Derby and dinner at Flying Fish. (At one time they had dining with an animal specialist at Sanna at AKL too - not sure if this one was discontinued). But it is a small group, about 10 people, and it is frequented by solos. Sometimes only one member of the family was interested, sometimes it is locals or big Disney fans. But the imagineer leads most of the discussion and it is interactive. You may even make friends.
After awhile you will likely get into the spirit and be so busy that you won't even be thinking about being alone! People tend to blend into the background when you are running around to rides!
