When to travel
First decision you need to make is when to travel. In December- January is the most expensive and most popular time. You can see that at least when you are booking the hotel.
In summer, from June to September is really too hot. There is no way to be outside, at all.
May and october are also hot, so i don't recommended if you have small kids with you, or you don´t really love the heat. These months can be +30c - +40c around the clock.
March and May will be perfect for them, who want hot days and warm nights.
December, January and February is the high season. Then the temperature is like +20c - +28c on days, evenings and nights are more cooler. You need to have long sleeves, maybe even a jacket at some point. Tourists are swimming at pools and even in the ocean, but water might be really cold.
All year sun is shining almost every day and the rain is rare. There is possible of sandstorms.
Where to stay
Dubai is big city and the distance are long. Metro is easy to use, but it goes long way. Taxis are quite cheap.
Places like Deira and Bur Dudai are pretty close to airport. Hotels are most likely within walking distance of the metro. These areas are not the fancy part of city. Hotels are often old and middle class or worse. Off course there is some exceptions.
Downtown is near of Dubai Mall and Burj Khalifa. There is plenty of 4 and 5 star hotels. Nice area, with everything but the beach. This is the shoppers paradise, if you have extra money to spend and you love luxus brands.
Al Barsha is area near of Mall of Emirates. There is some luxury hotels and also middle class hotels and lot of apartment hotels. I think this is great location, pretty near of Marina, Palm Jumeirah and shopping. Metro is close by.
Palm Jumeirah is Palm tree shaped island. There is almost every luxury hotel brands represented. There is huge hotels and private villas, expensive to really expensive. Hotels have the most spectacular pool areas and private beaches. Love this place, but is a bit far away, at least if you use the public transport. (off course it's normal to go there with helicopter, but it depends your budget) If you are looking for a place where you wanna eat, eat well and relax, Palm is perfect for you.
Dubai Marina / JBR is the place to be, in my opinion. There is mall, beach, marina, amazing views and really good walking opportunities. There is plenty of restaurants, from fast food to fine dining places. You can also find the most popular night clubs in this area. There is some free kids play areas and with extra charge trampoline, camel riding and all kind of water sports.