A few ways you can make your Google Ads business more profitable is by attracting more clients, or even by convincing your clients to increase their ad spend. However, this must be done with the clients' best interests in mind: so don't just persuade them to up their budget simply to receive more revenue. You need to do this strategically by explaining the benefits that your client will receive from increasing their ad budget, like the chance of gaining a higher Ad Rank. There's also the option of increasing your rate, but arbitrarily charging more for the sake of earning more is a little dishonest, if we're being frank.