I would first like to confirm that though this looks to be a really odd topic, an abnormal one, but this can prove to be a valuable one. We all like to have good language usage and for this we know that idioms usage can be of great help. But all of us are not so well when it comes to idioms vocabulary. Now, what to do? What I am going to say is something only good for the creative minds. One must not feel that I am trying to insult all those who are not creative in themselves. I am sure that everyone is creative. All I wanted to say is that if someone does not have a really impressive idioms vocabulary, then he/she can actually make his/her own idioms.
It seems to be a babyish game but it is not so. Creating idioms is not so easy. There are a lot many things to be considered and one needs to expertise in many of them. Without wasting much time, let me focus on these points which can let you make your own idioms in case you do not have a source to learn idioms and you don't have a good idiom vocabulary or even if you have a good idioms vocabulary but you need to use special idioms for special cases. So without any more backups, let me just start off with the points -
Relating things - To make idioms is not an easy bit. One must be quite talented to relate things and see what is the result. We all know that we the Indians have developed a very crucial talent to relate everything to politics in any way and speak of it's leeward side. Similarly, to create nice idioms, we must know how to relate things and know about them. We must relate things which can be related to the concerned idiom.
Be updated with the news - One needs to keep himself updated with things which have happened recently and things which have a big count. We can do this only by keeping ourselves updated with the latest news. This can be really helpful while making idioms because as has been seen, so many idioms are made according to the latest news. Not only the immature writers and users but also the mature ones are fond of doing this.
Good vocabulary usage - A good idiom is a signboard of good vocabulary. It is very much needed that we must use some sorts of rare words in the vocabulary so that anyone who reads it loves to know what it actually means. Good vocabulary has always helped to attract people. So good idioms always deserve to be garnished with good vocabulary.
Short - It is a common observation that all good and attractive idioms are short. Short does not mean that the idiom should be not more than two words. It shall extend itself to about 6 words at the maximum.
Classic - The idiom requires to be classic. It must give a sense that it has been composed by a mature culture. I used the word culture because idioms are not something which shall be exactly written or shall come into frequent use by only one person. Many people need to use it.
Idea Rendering - The idiom must render the idea of the actual meaning. However, it is not necessary that it should render the whole idea. It must render at least some idea so that the person who reads that idiom gets a chance to reason out the meaning of the idiom. However, sometimes, the meanings can be similar but the words can be fully alternative giving the same meanings.
Here is an idiom which I have created on my own -
Nail in the palm
Meaning - trouble for someone.
1. I am her nail in the palm, she looks to be very disturbed after seeing me.
2. She is a nail in the palm because she is really very boring.
I hope now you have understand. If not, let me explain. Why does Nail in the palm mean "trouble for someone". Imagine, what if one hammers a nail in someone's palm. It would be really a painful experience and a really painstaking experience while trying to move one's hands. I think that this is surely a thing of common sense that if a nail is hammered in someone's palm how troubling it would be for the victim.
Lets take another one which I have made, into consideration.
(As) on the ads
Meaning - To be in a hurry and in too much excitement.
1. I am really sorry to ping you so early in the morning like as on the ads, but I had an urge to be spelled out to you.
2. I am really on the ads for you because you have won the 'WOM' in ISC. Hearty Congratulation.
Now what is the composition of this idiom. It is really a short one and having only one remarkable word that is 'ads'. Why does it mean so or why have I made a meaning for this idiom as such? When we see our friends, relatives or ourselves even on a radio ad or a television ad, we are out of craziness, so much excited that we tend to jump, run and what not! Though it is not a fortune to everyone, it is to some of them. So this is the reason why it means so.