Marketing costs money. You must have a realistic budget and stick with it.

Research your current finances
You need to understand your current financial to create a budget. Estimates can vary. Consider your revenue information. Businesses can be feast or famine, particularly if you are in your first year or are a freelancer. Whatever you make in famine mode should be what you count on as your revenue. Feasting can be unpredictable and, therefore, should not be counted. Some businesses combine the profits from feast and famine and divide by two. This is not realistic, as you cannot rely on feasting. To reframe this, famine sets you will practical expectations for what you can truly afford during leaner months. When times are tough, marketing is usually the first cut when the opposite should occur. Leaner times should be the time to amp up marketing. By focusing on famine, you will never have to trim your budget thereby making your presence consistent. Also, any extra money can be put away for the unexpected and growth spurts. If you sell unique shoes, some celebrity or person of note my buy your product and spread the word. You will then by cut short if you do not have resources to meet the demand.
Research
Awareness is perhaps the best quality in an entrepreneur. Research helps in the process to enlightenment. Once you are comfortable with your budget, you must investigate past failures and successes. For example, if you took out an ad in the hippest magazine and it yielded nothing but prank calls, then you know you did not correctly target your audience. Afterwards, you may have sponsored a local event that was a smashing success. Targeting takes research and time. You may know going into your business what you want to attract, but life is surprising. As mentioned in an earlier post, a cereal bar wanted college kids but had the surprise audience of elementary school kids. They advertised on the college radio station, took out ads in the college paper, and handed out coupons. It did not work. Had they researched further, they would have discovered their marketing dollars would have been better spent on sponsoring a youth sports team and opportunities centered on the younger than expected target. Make yourself aware through research.
Monitor
You must have metrics in place. This is a requirement. If you expect to pour money into a strategy and have it work without paying attention, you are throwing away money. Pay attention! Analyze whether revenue has increased as a result of your efforts. Make allowances for seasonality and weather events. It is also important to note that you must also monitor yourself. Being realistic about money should cross over into how realistic you are about how much time you will spend on research, monitoring, and managing expectations.