3. Don't annotate all the points in your chart - it'll get cluttered. Only label key points, points of significance (eg: the highest and the lowest revenues recorded for the year)
1. Use as few colours as possible to convey your idea - try & look for means to group your variables in such a way that fewer colours can be used to convey your point better.
Eg: Top N products in one colour & the others in another, instead of one colour for each product
2. Use gray in your chart - it is strong enough to be distinguished from white so your variable won't blend into the background, and you can easily combine it with a stronger colour like red if you want to show contrast or highlight another variable