How can you hire and motivate people for monotonous tasks such as data entry?

• 1st and fore most give the job to the person who needs it. He should be a person in need for money. 
• 2nd the target audience would be students who are outstation or who need to earn their keep. 
• 3rd . the target should be young as typing speed decreases after a certain age. 

appreciation to them time to time ,fully watch their performance,display every employees performance,realize to them he is special for you.

in a hiring time-person'have patience and diligence and candid quality

Only way i recommend is to take a stroll every2 hours. Light music can also refresh the staff. if possible the staff should do some light exercise in the office. 

No doubt data entry to some is a monotonous task however people who opt for this job are aware that this is the ability they possess and have taken the job as their choice. However to keep up the excitement I guess ergonomics here plays a bit of a part that is if they have some lively and bright work stations and soft instrumental music in the background it would take away the boredom. IT can design the data entry pages too with some lively color & pattern.

By giving them some kind of incentives you can get ur job done in easy way.

By interview meeting and practice test

Give the needy and reward the needy accordingy

Pay Well, Don't pay the minimum but set your pricing to clients such that you can pay a fair and attractive wage to your workers. Also bonuses for overtime, exceptional work, etc are a great way to show you notice their hard work.

Good communication and relegation with stuff lead to request anything from them easily , also you can choose from young join stuff, thanks for invitation

First those people who will be able to do data entry work easily and who are interested for it will be seen.

Set a goal for them and make them comfortable 

If you are good to your employees they would want to work with zeal