General:
* Myślę o… (pronounced: "Mishlen oh...") - This is the most common and literal translation.
* Pamiętam o… (pronounced: "Pamientan oh...") - This means "remembering about" and can be used when thinking of someone or something fondly.
With a specific person:
* Myślę o Tobie (pronounced: "Mishlen oh Tobee") - This means "I'm thinking of you" and is used when thinking of a specific person.
With a specific topic:
* Myślę o tym, jak... (pronounced: "Mishlen oh tim, yak...") - This means "I'm thinking about how..." and is used when thinking about a specific topic.
Other expressions:
* Mam na myśli… (pronounced: "Mam nah mishli...") - This means "I have in mind..." and can be used when thinking about something specific.
* Przemyślam… (pronounced: "Przemishlam...") - This means "I am considering..." and is used when thinking about a decision.
The best translation will depend on the context of your sentence.