Learn More Than PHP
I am HUGE advocate of learning alternative languages and frameworks. So that means if you are a PHP Zend man, I would suggest learning another MVC framework like Laravel or any other PHP framework that looks interesting to you – there are many to choose from:
PHP programmers should learn a competing language
But … this may shock some of you hardcore PHP nerds, it’s also a good idea to learn another competing language too! Personally, these days, I would suggest learning a little Ruby. Ruby is very popular, sophisticated and by comparing how Ruby does things vs PHP … you will become a better PHP programmer because of it.