Here's some old tips along with a few of my personal favorites that might help you break through that songwriting block and get back to writing good songs again. Use a different approach.
Some songwriters write the melody first.
Some prefer to come up with the chord progression first and then write the melody. And still others prefer to come up with a rhythm or groove first and then write the melody and chord progression. There is no one correct way to write a song. However, if you're someone who always writes the melody first, try coming up with a chord progression first. Or, see if you can get yourself into a different groove by programming a beat on your drum machine and writing to a rhythm.