Budget Itinerary for Istanbul in 5 night 6 Days

Day 1:
Early morning flight from Mumbai to Jeddah at 4 AM
Layover time - 3 hrs at Jeddah Airport
Than another flight from Jeddah to Istanbul airport
Landed at Istanbul Airport at 2 PM Turkey time

Pick-up from Istanbul Airport and drop at Sed Hotel, Beyoğlu, Near Taksim Square, Istanbul

Evening time- completely free. Explored Taksim Sqaure by ourselves.(Taksim Square was 10 minute walkable distance from hotel).

Day 2:
First half - City tour (includes lunch, pick up and dropping back to hotel) starts from 9:30 AM and ended around 6 PM
City Tour covers below mention -
Blue Mosque, Hagia Sophia Mosque, Grand Bazaar and than lunch at local restaurant.
Post lunch visit to Bosphorus Straight via Ferry (90 minute ferry ride) , Pierre Loti, Cable Car, Eyup Mosque

Second half - Dinner at Cruise from 8 PM to 11:00 PM (includes pickup and drop)

Day 3: Istanbul Aquarium , Galata Tower , Grand Bazaar , Dinner At Swissotel
Left early from hotel after having breakfast.
Reached Taksim Metro Station by walk. At metro station only opted for Istanbul Travel Card (one card is required for 2 people and works for all the Bus, Tram and Metro).
Took metro from Taksim Metro Station ->Yenikapi
Now change metro from Yenikapi to Floya.
Explored Istanbul Aquarium

After visiting Aquarium, came back to Floya metro station and took metro to Yenikapi.
Again changed metro at Yenikapi and took metro to Sishane metro station.
Visited Galata tower at Sishane.

Came back to Sishane metro station and took metro to Vezneciler station and visited Grand Bazaar
(Grand Bazaar usually requires minimum 2-3 hrs to explore it properly which is not possible in City Tour)

After visiting Grand Bazar, came to Sultanahmet Tram station by-walk. Took tram to Kabatas tram station. ( My hotel was near from Kabatas tram station)

Later for dinner went to Swissôtel The Bosphorus Istanbul 16th Roof for dinner.

Day -4: Visit to Şile Aqua Beach via bus (include pick up and drop)
Bus picked us up from Taksim Square.
On the way, bus stopped at zoo known as " Park Of Istanbul " where you can see lion , tiger, ostrich, various species of lizards and get chance to play with 4 months old cub.
Later bus will stop at another point where you can get a chance to do ZIP-LINING over Black Sea.
After lunch-break, bus dropped us at the beach. There we got chance to swim in the BLACK SEA.
Finally bus dropped us back at Taksim Square by 9-9:30 PM

Under this Şile Aqua trip, zoo and zip-lining were not covered (self-sponsored). Only lunch and bus fare was included.

Day -5: Visit to Prince Island ( Adalar Island) and Uskudar (Asia Side of Turkey)
Left early from hotel after having breakfast, came to Kabatas Ferry Station by-walk. Took ferry to Adalar Island.
Its a 2 hr ferry ride and Adalar island is the last island out of the 4 islands.
Explored the island on foot and had lunch there only.
Purchased 2 tickets for Kabatas Ferry Station and decided to de-board the ferry at Beşiktaş ferry station to explore the Asia side of Istanbul.

At Asia side of Istanbul, you can visit Maiden's Tower(which is currently in renovation) and Çamlıca Tower.
I was not able to visit Çamlıca Tower as respective Metro was not working on that day and bus was taking a long time.

Finally took ferry from Beşiktaş ferry station to Kabatas ferry station and came back to hotel.

Later for dinner went to Taksim Square.

Day -6: Visit To Top Kapi Palace and Dolmabahçe Palace
Left hotel early morning.
Took tram from Kabatas tram station to Gulhane tram station. Visited Gulhane Park and Top Kapi Palace.
Later took tram from Gulhane tram station to Kabatas tram station and visited Dolmabahçe Palace.
Since Dolmabahçe Palace remain under maintenance on Monday's, was able to see it from outside only.

Came back to hotel as pick up was scheduled for return flight.

Dropped Istanbul airport at 2 PM.

Return flight from Istanbul Airport to Riyadh Airport.
Layover of 2 hrs at Riyadh Airport.
Flight from Riyadh Airport to Mumbai Airport. Landed at Mumbai Airport early morning and came back to Pune by cab around 11-12 PM.