FOCUS (verb): to bring to closer attention
For example, "Focus the lens of the camera" or "Focus when I'm talking to you!"
To focus on what is important means to direct all your energy and attention to what you think is important to your life. It could be something like family, school, health.
CAPTURE (verb): take into possession, catch or grab something
For example, "Capture a picture of this" or "The burglar was captured last night"
To capture the good times means to catch and hold on to all the good times you experience in your life.
DEVELOP (verb): create or grow something
For example, "Today I'm going to develop some pictures of our vacation"
To develop from the negatives means to produce and create something from all the bad (negative) things that may happen in our lives and make them into good things. In photography, the noun "negative" is also used to describe the roll of film created when taking pictures from a camera. It is very rare to see these nowadays because most of us use camera phones and it needs no film!
SHOT (verb): the picture (only in terms of photography)
For example, "I can't take good shots with this old camera"
To take another shot is actually an idiom (take a shot) to mean, give it another try, make another attempt. If nothing works out and you fail over and over again, just try again! Take another shot!