だけで

だけで is a combination of だけ (Only/Just) and で (“how”).
There’s more emphasis on the word before だけで than just using で alone.

With Nouns

With just
Noun + だけで

With nouns, だけで means “with just“. This is typically contrary to expectations. 

• かた足だけで立っている – He’s standing with just one leg.
• 二人だけで行こう – Let’s go (with) just the two of us. 
• 言葉だけで解決しよう – Let’s solve this with just words. 

で can also be the normal Noun “て” form and connect 2 sentences:

• 見ているだけで、何もしていない – I’m just looking and not doing anything. 

With Verbs

Just by
Verb plain form + だけで

だけで may also be used with verbs to express “just by“. It emphasizes that an action causes something else. 

• 考えるだけで怖い – I’m scared just by thinking about it.
• 彼女を見るだけで心が安らぐ – I feel at peace just by looking at her.
• この薬を飲むだけで若返る – You’ll get young again just by drinking this medicine.