I have been through this experience, and it is tough to ask for a raise within the first year. The best time to negotiate is when you receive the offer, after that, you may need to wait a little longer than three months.
Don't claim value; create value. Can you demonstrate how you are underpaid, in that you have data that show what other people in similar positions are making? You'll also need to clearly outline how you have added value to your employer. Simply stating you deserve a raise will not be as effective and showing them why and what you have done to deserve it.
In the meantime, look at ways that you could improve how your company operates. If you are bored, create projects for yourself. Your employer will love you for it in the long term and provide you with a strong recommendation in the event you want to get a new job. Creating value now will also improve how you communicate when interviewing for other jobs.
Don't claim value; create value. Can you demonstrate how you are underpaid, in that you have data that show what other people in similar positions are making? You'll also need to clearly outline how you have added value to your employer. Simply stating you deserve a raise will not be as effective and showing them why and what you have done to deserve it.
In the meantime, look at ways that you could improve how your company operates. If you are bored, create projects for yourself. Your employer will love you for it in the long term and provide you with a strong recommendation in the event you want to get a new job. Creating value now will also improve how you communicate when interviewing for other jobs.