Ideal clothing while traveling.
Basic outfit
Jeans
Tshirt
Sneakers
You can also wear
Slacks
Tshirt
Leather boots
But usually this second outfit is not very comfortable
Lounging in the house
Sweatpants or shorts
Sweatshirt / hoodie or tshirt
If you are going to be working from home or spending most of the time inside the house, then, this outfit is useful to have.
However, when you are traveling, or in general, avoid spending too much time inside the house
Temperature matters
Pick an ideal outfit for a temperature, and go with that. Likely the thing people will see most is the insulating layer, that is the sweater you are wearing.
Colors
Black is classic and avrious shades of black go together better than most anything else.
However, some color is useful. Usually a sweater.