Well, we just returned 2 weeks ago and I will tell you the tips we used that I found either enhanced, provided ease or more enjoyment to our trip.
1. We rented a car because I got a killer deal through my work for a Kia Sorrento for $163/week inclusive and we were flying into TPA and needed it at least for 1-2 days. We decided to keep it and budgeted for it. HOWEVER, the tips I used were:
we did not drive to MK or MK area resorts, HDDR or DTD. We took the boat to DTD, buses to MK (& then boat to HDDR) and all trips were very efficient and speedy. I know part of that reason was because we were there the last week of October and crowds were probably lower. We never waited more than 5 minutes for a bus. I know our experience isn't universal, which is why I was glad we had the car as back up. The only time it was a little "dicey" was coming back from MK at the close and the buses were full and either myself or my DH stood and the other held out daughter so as to only take up one seat. The car came in very handy for Epcot and AK. I know we made it to EP in 10 from POR. Got there early, had
AAA Diamond and walked in with the CM's. AK, the same way.
2. We did 2 breakfasts at parks we wanted to visit, thus, "forcing" us to get there early and be there before the crowds. When I say "force" -- we were not under duress...it really added to our enjoyment. We did Akershus and RFC at AK for breakfasts at 8:30. Consequently, we were done by 9:10-9:15 and on our way to fun.
3. We used fast passes like the pros. Considering it was our first trip to WDW, the only way we'd have known the "ins and outs" of using the fast passes (even though they are explained around the park) was this board. Strategy was key. We got a fast pass, then went to the standby for Soarin', BTMRR, Splash, Kali and others several times and it worked out great. It allowed us to ride our favorites several times back to back.
4. We took advantage of
MNSSHP to ride to our hearts' content. That party really provided us an awesome opportunity to practically walk on everything in MK and see the sites. I loved going to the party. It was awesome. POTC, BTMRR, SM, everything in Fantasyland....awesome, no waits. Loved, loved, loved it.
5. Bought park hoppers and used them. I'd advise, though, to add them after you get there. The reason we used them, is the opportunity presented itself and that's what worked for us. We had a short day and then we took a quick trip into MK before our ressie at Narcoosee's to ride my DD7's favorite, BTMRR! She loved it. I can see using PH's more when she is older and can go to more of the evening EMH's. They aren't for everyone. Budget for them, if you think you may want them, but add them later.
6. Went to MK more than we had planned. The best laid plans should be those than can change and are flexible. We also took a "day off" in the middle of our trip. We were exhausted because we were newbies that really wanted to see as much as possible because we didn't know if we'd return. We really thought this would be a once in a long time (lifetime) thing; however...that has since changed!
7. We really took in the sites of each park and each area of each park. We had to laugh at the Smucker's window beside Mainstreet Bakery because Smucker's HQ is in our area and we are so used to it and knowing people who work there. My DD7's classmate/friend is their granddaughter and we forget it's a famous name. I don't think she still believes it is her friend's grandpa that runs the company. She kept telling me I was wrong. LOL The commercials are true! Very normal, wholesome, kind family.
8. We (well, I) made lists for each park. The commercials are wrong. After you win the Superbowl, you just can't hop on a plane and go to WDW without a plan, people!

I guess if you are a millionaire, then you have a tourguide, so no worries, but the rest of us schmucks need some sort of plan...especially newbies. I'm not saying you have to plan yourself to death, but you do need a strategy. Maybe that is a better word. So, I took the advice of the Dis, got some travel guides, looked on here as well as the WDW site (and other sites...shhhh) and made lists of things that looked "fun/interesting" for OUR family. I had a card for each park. I chose restaurants that looked good to us and made ADR's. Surprisingly, we did most all the things on our lists and got the ADR's we wanted.
9. The silhouettes at MK. Best deal in town. You get 2 silhouettes for $8.00! That's right $8.00. AWESOME. They are speedy and very accurate. My daughter's was spot on!
10. Don't eat yourself to death just because you ended up getting FD with your package. We ate when we were hungry. We cancelled an ADR one day for lunch because we were full from breakfast still (it was our MNSSHP day and we didn't want an evening ADR) We were over by 1 ADR anyway because we had Narcoosee's. We each had 1 CS credit left when we departed. We took our leftover snacks with us to the airport.
11. Use guest services/concierge. They are so knowledgeable. The concierge checked us in the day before departure on our flight, even asked if we wanted to upgrade. Gave us awesome directions to everywhere and a great route to the airport -- no traffic. On our last day we were at MK and our dinner was at AKL at Boma. We knew we weren't going to make it (as much as we wanted to) as our DD and we, as well, were having too much fun at MK. So we went to guest services in MK and they cancelled it for us and got us into...hold on to your britches...'Ohana for that evening, which he, even said NEVER happens. We also used out AAA discount when we could. I also had Landry gift cards to Rainforest I had bought from my daughter's gift card program at school.
12. Took DD to Harmony BBShop for a trim and updo with pixie dust. It was beautiful. Cost $23.00 total and she got lots of compliments. She already has lots of the princess outfits and we knew with her hair (long, thick, curly) pulling it tight like at BBB would be "challenging" and uncomfortable for her.
13. Left before wishes was over. Wishes is beautiful, but to me, kind of nightmarish dealing with the crowds and mass exodus.
14. Took in Main Street Electrical Parade -- too awesome for words!
15. Bought the little card holder necklace from the resort gift shop. No more searching for our KTTW or CC's or anything. Love that little thing. Saved my sanity.
16. Finally, don't despair if something that was on your "to do" didn't come to fruition. I really wanted to see Illuminations, but my DD was tired, so we left after our dinner at Rose & Crown (which was stellar, BTW) I found myself making a mental check list of ...the next time we will have to do such and such. I guess there WILL be a next time!
If I have any other revelations I'll post them, but this has turned into a book as it is!

But these tips from this board went a long way to enhancing our trip! This board was so invaluable, I cannot state it enough!