I am quite often surprised just how many blogs don't have search boxes where their readers can search for subjects that interest them. Or, if they do have them, they are hidden towards the bottom of the page. If you have a search box like that I suggest you try searching for something - often the results show up right at the top of the page and then if you want to search again you have to scroll down to find the search box again.
So my suggestion is that you make sure you have a search box and that it is towards the top of one of your sidebars - probably right at the top under the header is the very best spot.
The search box is one of the basic gadgets available in Blogger - and I imagine in other blog platforms as well. To move it around you just need to go into Layout and drap and drop it where you want it to be.
Ps having piously advised you on this, I have just realised I hadn't yet put a search box on this blog.... sigh. Will now fix that.