Udaipur : City of lakes and VENICE OF EAST

Reach udaipur via train or bus or flight early morning preferably. It would be better of you have pre booked your hotel. Choose area near to lake pichola as most of the places you will visit are near to it.
After getting fresh, head out to visit the CITY PALACE. Book your entry ticket. You may or may not hire a guide. But if you are interested in knowing the history of that royal palace you should definitely hire one. The palace has amazing spots for clicking photos. Enjoy the tour and it's royalty. It can get crowded as the day passes so try to be early.
After the tour, you can also take a boat ride in the lake pichola, though its costly when done from inside the city palace. I would advise to do that fro outside the palace.

Then head out to visit the Lake Pichola. Enjoy the boat ride and take amazing pictures with the palace in background. The lake also has the famous TAJ HOTEL in middle of it. Once done with the ride, you can have your snacks and lunch in the nearby restaurants and cafes. After that you can visit the KARNI MATA TEMPLE, just beside lake pichola and on top of mountain. Take the ropeway ride for sure. If you visit the temple on Sunday, you can enjoy the delicious bhandara prasad there. Enjoy the sunset from the top.
After sunset, you an visit the famous LAKE FATEHSAGAR. Hire an auto. Many movie shootings have been done here including Yeh Jawani hai deewani. Take a brisk stroll along the lake with beautiful lighting. Munch on the delicious snacks at the cafes beside it.

All the main attractions of this city can be covered in a day if you are short in time. There are many other sites and places you can visit like the saheliyon ki bari, monsoon palace, bagore ki haweli, vintage car museum.

For shopping, area around City palace museum is best. Buy some souvenirs for family and friends.