Everyone - students, tutors and great mathematicians alike - gets stuck at some point. What is important is how you react to being stuck and what strategies you have for overcoming these problems.
Here are some tips.
Check you understand the problem or question
Look up any mathematical words or notation that you don't understand or have forgotten.
Can you explain what you have to find or do in your own words?
Do you need to make any assumptions or simplifications?
Try looking at particular or simpler examples of the problem. Using examples with numbers can sometimes help you to see a way forward with a more general problem.
Work out what you need to do
Try to break the problem down into manageable chunks.
Summarise all the information you have been given and the techniques that might help.
If it helps, draw a diagram.
Look back in your books and notes for similar examples. Will the same techniques work for your problem?
Discuss the problem with other people (not necessarily mathematicians!). This might clarify your thoughts sufficiently for you to progress.
Have a break - coming back to a problem refreshed can make it easier to solve.
Know when to stop
If none of these strategies work, stop and ask your tutor for help. It is important to keep on target with the course as well as developing your problem solving skills!