The best tip for achieving success after an ET is being relaxed at the very moment when the procedure is to be performed.
Besides, having a full bladder is strongly advisable, as it is a way for the doctor to observe your uterus through ultrasound in a better way. It allows for the doctor to place the embryo in the adequate location, without scratching the lining of the womb.
On the other hand, there are no "implantation foods" to boost your chances of becoming pregnant. If so, your clinic would prescribe them to you.
In fact, fixating on specific foods may cause more harm than good. Experts do recommend to follow a balanced diet from at least 3 months before your treatment starts. Avoiding processed foods, limiting your sugar, eating good carbohydrates, etc. could be beneficial.