My mother loved crafting and during my childhood in the 90s, there was not one craft that she did not tackle. Most of my resourcefulness and penny-pinching I can attribute to her. What I am most grateful that she taught me was faux calligraphy. This easily turns simple handwriting into something quite polished. I usually use this when I make my own cards, or on special messages. There are many tutorials out there that can teach you how to make amazing faux calligraphy but here are some of my personal tips.
Choose a writing utensil you feel comfortable controlling. Ballpoint pens, gel pens, and sharpies work best.
Practice what you are writing and how you want it to look on scrap paper. Use your normal cursive if you feel most comfortable. If you want to play with some of the letters by adding more space between them or by making loopier Fs, gs and ps feel free.
Write your message. After you write it, go back and retrace over the downwards strokes of each letter. This will thicken those lines. Do not retrace the parts of the letters where your pen moves upwards.