It's not exactly tough with the number of resources out there. Management providers can manage the server for you, outsource support can support your clients. Countless guides... the list goes on.
The only tough bit about it is getting clients, and finding your niche.
You need to persevere - don't expect to make a profit for at least the first year. There are many, many hosts - so the supply is huge. You need your niche to set you apart from other hosts.
You'll need a solid budget for both operating costs and marketing. Capital for your startup costs such as web design, marketing, software costs, establishment fees for a merchant account (Stripe and PayPal is free. But other merchants may charge), plus any other media such as banners, content, blog posts, SEO, etc.