Before I even started writing this, I am sure that the comments will be filled about how consolidating code makes it hard to understand, more braces make it easier to read, etc. This is for those who think it's better to have less code, such as yours truly. I like seeing less code; I find it more efficient and much better.
Short-hand mathematical operators
Those are known by most programmers however missed by a lot, the following can be shortened by its alternative next to it.
Counters
Here is another very simple one, but good to know for those who don't know about it.
Short-hand print statements
Ever find yourself have to write so much just to be able to echo a variable in HTML? No more!
Could just be
Ternary operator
My personal favourite saves a lot of time and I still think it makes readable code
Or why not...
You can even set variables using that method
Verifying zero values not being false
Sometimes we deal with a function that can return a number and we want to make sure it returns a number, but if it returns 0, PHP will consider it as false.
The number can return 0 and be as false, whereas the following will not consider the integer 0 false
Alternative control structure syntax
This is a great feature to do when you're trying to do a lot of PHP work with HTML, it would be hard to list all of them but you can refer to the alternative syntax.
Feel free to post any other ones in the comments section.. we all have that one trick we always use!