Some people see 'luck' as a force that operates for good, or otherwise, in shaping circumstances or offering opportunities. It is a chance happening beyond a person's control and there is a natural urge to improve good luck, or at least avoid bad luck. Lucky Charms, Lucky Symbols and Lucky Rituals are used to achieve this.
There are numerous lucky charms, symbols and rituals including lucky talismans, such as a rabbit's foot, a cross, a four-leaf clover, or some other Pagan related symbol, lucky rituals, such as crossing your fingers, choosing a lucky number or making the sign of the cross, wedding superstitions such as the bride's veil, the best day to get married, wedding rings and decorating cakes with lucky horseshoes
...and despite what Ads by Google may be claiming on this page, it's rather absurd to believe that any of these things can influence luck.
Some things in life can never be influenced. The place one was born in, for example, is fixed in history. You may feel it was lucky to be born into a wealthy, stable, loving family environment, or unlucky to have been born as a gnat. Or not. But no sane person would expect a lucky charm to change things that have happened in the past.
Accidents happen, good or bad, and certain people are accidentally caught up in those circumstances. That is chance. Or luck, if you prefer that word - it means the same. As irrational as it may be, the accident becomes personal and the person feels lucky (or unlucky).
If a person really does want good luck - and let's be honest, who doesn't? - then we need to find the source of luck and try to understand it. Otherwise, throwing salt over our shoulder is a waste of time. And salt.
Whatever 'luck' is, this cause of accidents that becomes personal, it is certainly not an entity that we can control with mere symbols. We are talking about a spiritual essence that needs a spiritual response from ourselves if we wish to influence its direction. And for a religious person, this obviously points to prayer.

Aids for improving luck
Prayer can be accompanied by a 'lucky charm', be it a rosary, a cross, location, time of day, etc. But these are merely props or prompts. The prayer must come from the heart of the person. A lucky charm has no supplicating ability to pray on our behalf.
Some argue that certain items (relics for example), or rituals (Holy Communion for example) are blessed. Sceptics dismiss this since such things have no soul to be occupied spiritually. And the debate goes on. At a lower level of thought are the mass-produced 'lucky charms' sold at inflated prices to people who believe such items holding mystical power, without thinking just when and where in the manufacturing process any mystical power might be infused.
An expensive gem encrusted cross is as powerless as one made from straw. Hail Marys will not improve one's fortune, neither will observing Ramadan, Feng shui-ing the furniture arrangement in your bedroom, being vegetarian, being circumcised, teetotal, or following any of the host of other things we feel led to observe. At best they are placebos, encouraging a more positive outlook that helps to recognize and seize good opportunities that present themselves.
If, and only if, luck can be influenced, then it is only a similar essence such as prayer that can influence it. And if God, or whoever we pray to, does not want such an event to be influenced, then there really is nothing we can do about it.
And if we can't do anything about it then certainly a rabbit's foot has no chance.