- "Тот" is not needed. Even if it was needed, it should be "та" because "напряжённость" is feminine.
- "между" requires Instrumental. Therefore "практический" and "главный" should be in plural Instrumental, not in singular masculine Nominative, "нужды" - in Instrumental, "решение" - in plural Instrumental: "между практическими нуждами и утопическими решениями".
- verb "to be" = "есть" in present is normally replaced by dash in Russian (+ Nominative). Or, alternatively, for the formal style "является" + Instrumental can be used.
- "главный" should be in neutral gender when used as object rather than attributive.
- "на" is not a way here. It should be "для" + Genitive or "в" + Prepositional.
- "understanding of" = ''понимание" + Genitive.
- "коммунальный" means "municipal" or "domestic", here "communal" should be "общественный" (in Genitive singular feminine because "традиция" is feminine).
Finally: Напряжённость между практическими нуждами и утопическими решениями - главное в нашем понимании общественной традиции в Америке.
This is grammatically correct although not perfect stylistically and semantically.
Maybe you'd better start with some theory and simple exercises?