0) Before your trip, inform yourself about the best places where to buy things.

1) The things needed the most.

2) Things with the least warranty trouble if bought elsewhere.

3) Things currently the hardest to get. Buy them first before other things with which they must be combined. E.g., during the mining / Corona crisis and for building a desktop, the first thing to buy was the GPU and the second thing a high end power supply unit.

4) Things surviving transport.

5) Things for which you can pay any customs and tariffs.

6) If it is not about electronics but other things (such as books), first locate any desired rarities.

7) Bags etc. with which to transport the items to be bought. Also you might want to locate post offices and find out their opening times.

"What are the best items to purchase overall and specifically on the first day of a shopping trip? Additionally, could you provide some general tips for a successful shopping experience?"