Here are some good tips for your titles, especially for your H1.
1. When creating a H1 title (your first title, hence the number 1) it needs to be catchy and grabbing, this is your golden ticket to increasing traffic, wider audience and higher ranking.
2. You need to create interest, emotion and curiosity in your titles to make your post irresistible.
3. Every theme's font and size is different, but mine on my BR site is 48px so going by this I won't use more than two lines. Some people use more, but I don't think that's good practice because it becomes difficult to read. The last thing you want is a full story in your titles, it's just not cool and can put people off reading your content.
4. If you want a huge title, try to refrain by adding the most important words for the first two lines - remember quality beats quantity. To express yourself further, you can create a small paragraph at the top of your article in bold - many sites do this and is very effective.
5. Shorter titles are more attractive - one to two lines.
6. It has been proven that negative numbers draws people's attention, not positive.
7. Avoid using the same word twice.
If you're ever stuck what to use, here is a catchy phrase title generator / template that I found on Google some months ago and often refer to myself.
I hope this helps