Now - you CAN use chalk markers, I am just too cheap to do it that way, so I use plain old school chalk.
1.I use baby wipes to clean my chalkboard off, but I never really worry about getting it perfectly black, because the more perfect your background is, the more your mistakes will show!
2. I make a general mock up online of what I want my font style to be. I don't know about you, but my default handwriting is not so pretty, so it helps to have a sort of template to refer to when I am actually printing on the board.
3. I keep a bowl of water on the table to wet my chalk. I don't mean dampen, I mean I really WET it. Repeatedly. It gets slimy feeling, and that is when you are good to go! As you are writing, it will start to dry out, so dip it again! It almost goes on more like a paint.
4. I use another baby wipe to wet the chalkboard where I am going to write, and then I do the general outline of my letters. This doesnt have to be perfect, it is more just so I know it fits before I go back and work on making the writing more stylistic. When you first use wet chalk - it is going to look like it isn't really there (see below). GIVE IT TIME TO DRY. I promise you that if your chalk is wet enough, it will dry nice and crisp.
5. Once I have my words on, and spaced correctly, I go back over and make the letters pretty. If you mess up (which I do often!) just erase that section, and rewrite it. Remember to be wetting your chalk the whole time. You can add banners, flourishes, whatever floats your boat. As you can see below - I do re-wet my chalkboard whenever I am adding a new element.
6. Walk away and let it dry. Live with it for an hour, a day, whatever - decide if you really like it. For example - I did the above board a few hours ago, and now that I have seen it for a while - I think that the 'thanks' needs a little work.
Sorry this picture is not great, I didn't want to distort the final image through editing! So...like I said - NOT perfect, but with a few simple tips it is definitely easier to get a more crisp chalkline!
If any of you have any chalkboard tips, feel free to leave them in the comments! I have lots of room for improvement!