Congratulations. Yeah, like others say, drive normally until you reach 90C on the dash (what on Giulietta (at least all 1.4) is shown when coolant on thermostat reaches 70C and still up to mid 90s I think).
Probably you anyway did most of break-in already, but I think you did it OK. Some say to run slowly, but that uses low rpms, and is not good (actually very bad) for engine, especially one which is during break-in phase. There are opinons that 90% of burn in happens within first 20-30 miles, and once engine is hot you should ride the car like if you stolen it, and important to also use engine to slow down from high rpms. Not sure about that method, for me it seems bit extreme. I read it, but I went for compromise both on my Honda NC750X bike (low rpm engine, redline at 6.5krpm) and wife's Giulietta 1.4TB (other cars I had 2nd hand). I drove normally trying not to exceed 3.5krpm before engine was hot, and then allowed myself for 4, ocassionally 5krpm for first 500km. I didn't use low rpms at load (say below 2krpm at all). After that 500km I allowed bit more rpms, and at 1kkm I went to redline from time to time. I used engine to slow down often (dynamic drive forces this anyway).
On motorbike I had mandatory 1kkm service with oil change, I did it at 900km. On Giulietta I changed oil after 5kkm (1 year, car not used that much), but if I was doing it again, I would probably change also after first 1-2kkm.
Afer 2 years G shown 127BHP on dyno, and went into 147BHP @ RON98 after ECU mod (mod was not extreme, there was still a lot of headroom). Runs nicely, so I'm happy.
Regaring oil changes in general. Do it every 10kkm(6kmiles) if you drive on the city mainly, or 15k/9kmiles if you do motorways only. Not less often than once a year. It is important for 1.75 turbine mainly (on 1.4 MA for MA module), but in general applies to every modern & complicated engine like ones with turbo- all service intervals given in instruction manuals are for falsing people that it is OK, lowering theoretical costs of usage, but then after 100kkm engine often is already used or with problems with plenty of deposits of old oil etc. Manufacturers are happy, that happens after warranty, so people pay more for service in a few years time (e.g. on TBI turbo failures), and then scrap your car earlier, and car business is doing well.