At lunch, follow the locals to a trattoria. Once there order a litre or mezzolitre of their vino Roso de la Casa. Enjoy the wine with a good meal. If you chat up the owner and express your desire to try a good Tuscan Italian Red Wine. With much pride they will show you what they think are good wines and will recommend certain wineries and will likely arrange for you to visit that winery.
At the winery you will get a truly personalized taste of their Tuscan Red Wines. In addition to tasting good wine and buying a bottle or two, you will have a memorable experience.
The second way to find the best Tuscan Italian Red Wines is to locate wineries that are in Tuscany and travel from winery to winery sampling their wines. I do caution you that you might want to sign up for a wine tour if you are doing this option. The Italian driving under influence (DUI) limits, are quite stringent.
There are maps available online for your review and there are companies that specialize in wine tours through Tuscany.
Italian red wines especially those in Tuscany are great. It is hard not to find good Italian red wines in Tuscany. I encourage you to eat and drink your way through Italy and experience the Italian lifestyle.