Don’t say: 
– I need go home.
– I needed buy a new car. – or – I needed bought a new car.
– She wants speak better English.
– I want find a good job.

Say this:
– I need to go home.
– I needed to buy a new car.
– She wants to speak better English.
– I want to find a good job.

Need and want are not the only verbs like this,  Here’s a list of others.

— Thanks to Laurie for this article —