Catch the Tokyu Tamagawa Line from Unoki toward Kamata and transfer at Keikyu Kamata to reach Shinagawa for the Shinkansen; this gets you to the Tokaido Shinkansen gateway with minimal transfers.
Stop at Komeda's Coffee (or a nearby bakery/kissaten) for a hearty Japanese-style breakfast and coffee before the long ride; Komeda branches usually open ~7:00 so it's reliable for an early start.
Board a Tokaido Shinkansen (Nozomi/Hikari) to Shin-Osaka; this is the fastest door-to-door option and gives you comfortable travel with ekiben (train bento) for lunch if you prefer.
From Shin-Osaka follow signs to JR or Osaka Metro. The quickest path to Shinsekai/Tsutenkaku is to take a JR local or subway toward Tennoji/Namba and transfer to Dobutsuen-mae (Sakaisuji/Midosuji lines) for a short walk.
Enjoy Osaka’s famous kushikatsu (deep-fried skewers) at a well-known Shinsekai spot like Kushikatsu Daruma; lunchtime menus and set courses make this a great introduction to local flavors. Many places are open 11:00–22:00.
Climb or ride the elevator up Tsutenkaku for panoramic views and to see the iconic Billiken statue; the tower gives a compact history of Shinsekai and great photo ops. Typical hours: about 10:00–20:00 (seasonal) — check current hours before you go.
Stroll the retro Shinsekai streets, browse souvenir shops and try small street snacks (takoyaki, kushikatsu stands). The area is open all day; it's a lively immersion in old Osaka.
Choose between a relaxed walk in Tennoji Park and a visit to Tennoji Zoo (park typically 9:00–17:00; zoo admission ~JPY500) or head up Abeno Harukas (Harukas 300 observation deck, typically open ~9:00–22:00, admission ~JPY1600) for a skyline view near Tsutenkaku.
Return to Shinsekai for a bigger dinner (more kushikatsu, okonomiyaki or local izakaya). Good chains and local spots usually serve until 21:00–22:00, giving you flexibility.
If you want classic Osaka nightlife, go to Dotonbori for bright lights, riverfront walking and dessert treats (takoyaki, parfaits). Dotonbori is lively at night and open late—perfect for photos and snacks.
Head back to Shin-Osaka (or your hotel) by subway/JR; trains on major lines run until around midnight but check the last train times if you are staying farther out.