If you have any of these filters, then practice with them.   What do you need to do to achieve the strongest effect with a given filter?

 

If you don't have any of these filters then try these:

 

1) Stretch stockings or tights over the lens

2) Stretch cling film over the lens

3) With the cling film, make a hole in the middle of the lens

4) Use a coloured, see through sweet wrapper or similar over the lens

 

 

Find out what size filters your lens requires.  Have a look online and see how much different filters might cost.