If you want to blog, you need to blog on topics that you like and the topics you know very well. If you enjoy travelling and have travelled to a lot of places, travel blogging can be a good idea. If your interests are in cooking and if you can write recipe articles, you can concentrate on a recipe blog. On your recipe blog, you can publish about traditional and ethnic recipes which are very popular these days. If your interests are in gardening, you need to work on this topic. The best topic is always the topic that you have command over.