When you've gone to all the effort of writing a good post, it kind of sucks for it to disappear off the face of your blog after a short period of time. That's unfortunately what what tends to happen without decent blog navigation. You write a post, it sits on your homepage getting views for a while and the more time that passes, the more it gets buried under a sea of posts, never to be seen again. So ideally, you want to set up a number of systems to ensure your posts are still available for people to view.
When people don't have a search bar on their site it's a big bummer because it's such a missed opportunity. It's the easiest and quickest way for a reader to find something on your blog. If someone wants to know for example if you've ever reviewed a certain product or if you've done a post on... I dunno... dry skin or what have you, all they have to do is type a few words into a search bar and they'll know.
Blogger has a default search bar gadget that you can add to your layout, but I must admit it's not my favourite in terms of esthetics. I put up a code for a nice simple search bar in my recent 5 More Ways To Clean Up Your Blogger Template post for anyone that's interested.
Another easy way to make your posts accessible is to have an archives gadget. I think it may even be a default part of Blogger layouts if I remember correctly. It's handy though because everything you've ever done is right there in a clear format. It only takes a few clicks to get to where you want. Plus, as a reader I find it interesting to look back on somebody's body of work – to see how long they've been blogging and how their blog has progressed.
Pages and Categories
There are lots of ways to organize your posts. I definitely wouldn't say that there's a right way by any means, but just that I think it's worth considering finding a way to divide up your posts into categories so that your readers can peruse based on their interests.
What I did for this blog was divide things up generally into Pages (Makeup, Skincare, Life) and then to divide them up more specifically into Categories (which I used the Labels gadget to do). But again, find a system that appeals to you.
What you'll see on a lot of blogs is a “Related Posts” (or a “You Might Also Like”) gadget, which uses thumbnails to link you through to posts that are similar to what you're currently reading. It's one spiffy gadget. I can't tell you the number of times I've gotten to the end of a post and found myself drawn into another by that gadget. There are a few different ways to add a Related Posts gadget, but the best system I've found is through nRelate. You have to make an account with them in order to add it, but they have a lot of styling options and you can decide whether you just want the gadget to show up on your post page, your home page or both.
Another common one is the Popular Posts gadget. As the name would suggest it showcases your most popular posts in a given amount of time (you can choose the time frame). Unfortunately, I think a lot of people avoid using this gadget because the default layout for it in Blogger 'ent the prettiest. The thumbnail size is annoyingly small. The good news is that it's not too hard to change the look of it. I used this site as a basic guide, and then a made a few further adjustment to the CSS, such as setting the boarder radius to 0px (to remove those curved edges) and removing some of the border lines. It just takes a bit of tinkering.
Alright, this one is not really about the navigation on your blog per se, but I'll explain. First off, I really recommend having a link to your Bloglovin' account somewhere on your blog. It's such a great way to gain readers, especially in the beginning when your blog barely shows up on search engines. Regardless of that, Bloglovin' provides a really clean layout for people to quickly scan through everything you've done. I often use the site to check out people's posts and to get an overall feel for their blog. Don't underestimate the power of Bloglovin' people! It's a thing of beauty.