As a full-time evangelist, it is important that you have the proper recordkeeping for maintaining the necessary records for filing your return. You should maintain a log of each place you ministered, showing the date, place and amount received. You should keep an expense log (computerized or by hand) showing the various qualified business expenses you would incur while evangelizing.
Another item you should be aware of is that you have a “tax home.” You need to have a place you call home, where you have housing expenses and where you receive your mail. Without a tax home, the IRS would construe you an itinerant, which means that all travel expenses and certain other expenses would not be deductible.
Every evangelist should have a designated housing allowance. This would allow any housing expenses to be excluded from income taxes; however, you would be required to report the amount as self-employed income on Schedule SE. A housing allowance must be designated either (1) by each church in which you minister, or (2) “other qualified organization” (Code Section 1.107-1(b).
Since you do not have an employer for income tax purposes, you need to be sure that you prepare for the future. You should set aside funds for retirement each year so that you become prepared for that time in the future in which you would desire to retire.