Dpi, scanning and image sizes doubts.

[Midgardsormr]

I'll mention something that frequently gets left out, and that's paper quality. If you're printing to typical copy paper on your home inkjet printer, don't use 300 dpi. The ink will saturate the paper, and your colors will run. You'll may also get some on your hands if you handle the document within a few minutes of printing it because it will take longer than you expect to dry. Even a laser printer will likely give unsatisfactory results if the paper is not suitable. Some printers are better than others at not overloading the page, but even the best cannot give you a high quality print on low quality paper.

[Gamerprinter]

Paper is everything in printing, and consider that paper is the least expensive part of printing compared to the cost of ink (I use a color laser for all my non-large format maps; 12" x 18" and smaller prints). So spending a bit more on paper is not unreasonable and will always improve the quality of a print. For inkjet, I'd stay away from bond paper altogether - except for draft printing. Inkjet paper has a coating on it to minimize bleed through the paper, bond paper has no coating.