If you're anything like me — juggling paying work, parenting, home life, errands, fitness — you might find limited time to sit down at an actual desk to blog or work on your blog-related tasks. So here's a roundup of plenty of things you can do while you're on your smartphone or tablet.
A few of these links are affiliate links, but most are just free apps. I use what I recommend.

Draft a blogpost.
If you're a minimalist blogger (mostly plain text), you might be able to post from your smartphone using one of the blogging apps (WordPress, Blogger, Tumblr on Android & iOS), using email uploads (Blogger, WordPress.com, self-hosted WordPress), or navigating to the site on mobile.
For me, I find the apps and mobile experience inadequate for all the images and coding and customization I love to cram into my posts, so I prefer to finalize things on desktop. BUT, I can absolutely WRITE a blogpost draft while I'm out. I just prefer to do it in email. I use Gmail's Inbox app and like that it saves my drafts well. I just pop my own address into the to field, make the subject line my title, and then Swype away in the text field. I'm Swyping this right now, matter of fact. I'd like to experiment, once I figure out the best headset, with dictating blogposts while I walk, using Dragon Dictation, the native Google voice-recognition on my phone, or another speech-to-text capability. (Here's how one person does this via Evernote.)
Edit your drafts.
If you have a blogpost draft you want to edit, email it to yourself or upload it to Google Docs and use the Google Drive app (Android & iOS) to access it. It has a nice autosave feature, and it will sync with your desktop version of course.
Check and reply to email.
I find being on my phone actually makes this easier, because brevity feels right. Bam. Email done.
Read other blogs.
I use Feedly for my subscriptions now, and I've learned the mobile gesture shortcuts to make the process easy. Save for later articles you want to read in depth or share, or just do it now if you have the concentration time.