1. If you don't understand the from of a twelve or eight bar blues you need to. Blues is highly structured for the most part, if you understand the form and can keep track of where you are in it then you won't have any problem with knowing where a song is going.

2 and 3. Listen to lots of blues music, there aren't all that many hard and fast rules when compared to jazz, it's mostly going to be in your gut.

bgood's advice to learn licks is pretty good advice, you may not be able to master so many licks starting out, but you'll find some new licks of your own.

Learn more then one position to play a blues scale in. You are probably playing with your index finger rooted on the one. Figure out how to play a blues scale with your pinky finger rooted on the one. Different hand positions will lead to different licks. Learn blues scales rooted on the 3rd, 4th, 5th and sixth strings, figure out how to move from one position to another changing from index root on the sixth to pinky root on the fifth. The more dexterity you can get moving from position to position will produce a grater variety of sounds and ideas.

Try to play with someone better and try to find someone to teach a basic blues scale too, jam with them. Teaching people and watching/listening to better players brings pretty good insight.

Listen, Listen, Listen is probably the best way to learn about the blues.

Try playing a pentatonic scale over blues cords or play a major scale with a flat 7 and toss in a flat third. These all give different textures and are used by different players.

If you don't understand some of what I'm saying you probably will in the future if you stick with it.