Hi there. I was a first timer last June. The first thing I will say is take the advice that is on this forum - I found it priceless! And you will absolutely LOVE your time in disney
Secondly, it depends on how you are attacking the parks. I went for rope drop so had a substantial breakfast and did not need to eat again until the evening. (If I got peckish a snack in disney is the equivalent of a meal for me!) Other than the fireworks on a couple of nights we left the parks around 6. Obviously if you are not an early riser than you need to factor that in.
Thirdly - I invested in a water bottle and refilled at the water fountains, I really struggled with the closeness of the heat and this was probably the best piece of advice I picked up. I am a diet coke fiend and easily could have spent 500 dollars on that alone.
Forth.. character meals can be extortionate - we did crystal palace breakfast on our first morning which was fantastic and not too badly priced. The bonus was that the park was empty so the first view of the castle was special - a memory that will stay with me forever. Later we did princess breakfast at akerhaus which was exorbitant price wise and the food not a patch on crystal palace. I enjoyed the characters more than my 5 yo niece ....
Fifth- being at the parks for ropedrop meant we were shattered by 9/10 so a big ts meal on an evening was just not possible. I think I may be one of the only people who go to US and actually lose weight!! Don't get me wrong, I am overweight and love eating, I just covered so many miles (200 in 14 days - I took a pedometer) that my bed was more
appealing than food

we had a few evening snacks at dtd as we were staying at bvp , Earl of Sandwich and Wolfgang pucks were worth the money. Also got restaurant.com vouchers for house of blues and had a fantastic meal there, made more affordable with the voucher.
Sixth..... i am sorry to say this but we ate ate at rainforest cafe (ak) and it was a massive disappointment. Ridiculously overpriced and bland. We had several much better meals with a few alcoholic beverages at millers ale house for about a 1/6 of the cost. You can justify the taxi by the saving.
7th.. best ts for us on property was prime time at hs. Still expensive but a really good interactive experience. We did not do many ts but this was our favourite.
8th ... don't waste your money on wishes dessert party, the food simply was not worth the monet, hang with the crowds instead.
I absolutely loved wdw. I am so glad I discovered this site and did not underestimate the planning that is needed. I went with the family, but I am a single 35 yo with no children. The children held me back!!! The rest of the family did no planning at all. I pride myself that their holiday was made better by me discovering this forum. I made the adrs and used restaurant.com gift certificates to the max. Make yourself familiar with the park maps, whilst it is unbelievably big it is manageable. Leave food choices to when you are hungry unless it's a special event or a ts that needs an adr. It's hard to eat at Epcot if you are in mk, have fp and it's just starting raining.... it is possible to overrplan. I get fed up of cs in the parks after 2 days (i am allergic to potato so the fast food was difficult for me) but i will say the burgers topping stations werr brilliant. We did a walk in at prime time and waited 20 mins, I did not consider this a long wait without a reservation.
I spent 1500 dollars in the 14 days, about 300 on gifts and the rest on food, drink and taxis (after a 3 hour failed attempt by bus to universal studios - I decided taxis were better - no fault of anyone except me accidentally taking my 5 yo nieces ticket instead of mine

) I could have spent much less, and equally much more.
More importantly. .. have a great time!