If a muscle is sore, do not train that particular muscle until it has fully recovered. It is ok to train muscles other than the sore muscles, just don't train the sore one. When working out, do not favor body parts. This can cause muscular imbalances. For example, having a big upper body and skinny legs is not balance.
Proper balance is a necessity.
If it gets to the point where muscular imbalance becomes a problem, try priority training. This concept involves training a lacking muscle first or with the most attention. For example, if the legs are not in proportion with the upper body, train them at the beginning of the week instead of training chest at the beginning of the week. For some, training a certain muscle twice a week may be the solution to muscular imbalances. Gym safety is important.