Aishwarya,
I'm definitely in agreement with the others! Especially as you're flying both inbound and outbound from Rome, eight days is simply not enough for a stay in all the places you've listed. If you were using open-jaw flights (ie: inbound Venice, outbound Rome), that would provide a bit more touring time.
Depending on what time your flight arrives, something along these lines might work for you.....
- Mar.28 - D1/N1 - Arrive Rome; Buy tickets at airport rail station for trip to Rome and then to Florence; take Leonardo Express from FCO to Roma Termini (DON'T forget to validate your ticket prior to boarding the train, or hefty fines may be charged); take Freccia high speed to Florence (90 minutes). Note that your destination station will be Firenze SM Novella.
- Mar.29 - D2/N2 - Florence - touring (if you're planning to visit the Uffizi or Accademia, reservations are advisable).
- Mar.30 - D3/N3 - Florence - possible day trip to Pisa or Siena (use train to Pisa, Bus to Siena - if you decide to do that, I can provide more detailed information).
- Mar. 31 - D4/N4 - Florence - you could take a day trip to Venice (~2 hours each way). More below on why I'm suggesting this method.
- Apr.1 - D5/N1 - Train to Rome in late morning/early afternoon (90 minutes); light touring in Rome.
- Apr.2 - D6/N2 - Rome - touring (plan carefully so you don't waste any time).
- Apr.3 - D7/N3 - Rome - you could take a day trip to Naples if desired (~1H:10M each way via high speed train).
- Apr.4 - D8/N4 - Rome - touring
- Apr. 5 - D9 - Return flight to India.
This suggestion "ticks" most of the boxes on your list, although it won't provide much time to look around each place you'll be visiting. Given the fact that end of March is not too far in the future, I thought it might be prudent to limit the number of "moves" and number of hotels you'd be using, to maximize your touring time. Each change of location usually requires at least half a day, and there's some cost as well.
Regarding "suggested hotels", I would highly recommend (given your location) that you download a copy of the Italy 2015 guidebook as an E-book. You can choose either the Kindle version (which can also be used in free Kindle Readers for PC, Mac, iPhone or iPad) OR the iBooks version. The guidebook has many listings for reliable hotels in various parts of each city and various price ranges, along with website information. There's also a LOT of information on restaurants, sightseeing, transportation and just about anything else you'll need to know about travelling in Italy. When choosing hotels, I'd suggest not choosing on price alone - be sure to consider which part of each city the hotels are located in. In Florence, the area around Firenze SMN station is fairly central, and in Rome the area around Roma Termini station is central.
You'll also need to be aware that there are some potentially expensive caveats when using trains and other public transit in Italy. If you need more information, post another reply here and I'll send you a PM.
There are many possible ways of arranging your Itinerary, and this is only one suggestion.
Good luck with your planning!