Tape takes practice. I've done it at least a dozen times, but it's still hard to get it exactly as I like it. Recently, I had my bars wrapped by a pro, and he definitely did a better job than I can. I suggest starting with cheap tape and be prepared to throw it out and start over if you screw up. Use stretchy tape, as it is more forgiving than tape that doesn't stretch (e.g., Lizardskin).