Petrol station hitchhiking
Petrol station hitchhiking is especially great in countries where there it's not allowed to hitchhike on the high-way and where there are enough but not too many gas stations on the highway. At most gas stations everyone is mostly going your direction, though you have to be aware of high-way crossing.
In Germany you should possibly avoid the "Autohofs", they're not great, since there is no clear direction.
It can be useful to connect to the people who work at the gas station. Asking drivers directly is a good way to catch a ride. For girls it's recommended to can ask generally where they are going so you can always pretend to not go there if you don't feel sure about it. Asking specific places can be good as well.
Starting a conversation will give drivers more chance to look at you as a person. It makes it less likely that they will send you away.
In Italy you have to be careful. It's illegal to hitchhike on the autostrada, it's a bit unclear if it's illegal on the gas stations on the highway as well.