Think!

THINK is clearly a verb. We know it very well and think that we know everything about it. Well, I want to show you something rather surprising about verb THINK...

We usually say:

I think that...
Uważam, że... / Myslę, że...

I'm thinking about...
Zastanawiam się nad...

Verb THINK is usually a STATE VERB, which means that we do not normally use it with -ING ending (= in continuous tenses). However, when it doesn't mean 'believe or have opinion that' (Uważam, że...), but 'consider something' (zastanawiać się nad czymś / rozważać coś) we can use it in the continuous form.

I think that we have made a serious mistake.
Myślę, że zrobiliśmy poważny błąd.

- What are you thinking about? 
- I'm thinking about changing my job.

- O czym myślisz?
- Zastanawiam się nad zmianą pracy.

We can always use an adverb to modify the verb THINK:

I personally think that....
Osobiście uważam, że...

I really think that...
Na prawdę uważam, że...

I honestly think that...
Szczerze myślę, że...

We can think deeply (poważnie / dogłębnie), carefully (dokładnie / uważnie), long and hard (długo i intensywanie), rationally (racjonalnie), frantically (szalenie) etc.

There is also a possibility of using an adjective or even a noun after verb THINK!

Let's see...

Think big!
(Try to achieve a lot!)
Postaraj się osiągnąć jak najwięcej / więcej

If you want to make money you have to think money.
Jeśli chcesz robić pieniądze, musisz myśleć o pieniądzach.

So, if an adjective follows verb THINK it means that we need to think in a particular way and when there is a noun behind it- it means that we need to think about this particular thing.

Compare:

think differently = think in a different way 
HOW should I think? = differently
pomyśl inaczej

think different = think about or of (something) different
WHAT should I think of? = (something) different
pomyśl: inne / inny

By the way, THINK DIFFERENT was a slogan used in Apple advertising in 1997:

THINK PINK!

I have come across this funny piece from Funny Face musical where an editor explains what a magazine should be (explicit!) and then she invents the new trend: THINK PINK! Have a look:

It turns out that nowadays fashion magazines also promote THINKING PINK ;)

THINK SMALL

And the last classic example: THINK SMALL from the VW advertising:

What can I say...

THINK ENGLISH!