#1) If your guide, masterlist, etc. takes up more than a screenlength on the dash, please put it behind a cut. If you're editing in rich text, you can click the button that looks like two solid rectangles with a dashed line between them and it'll put it in automatically. Yes, it means that when it's reblogged, it'll be a link back to your blog, so if you change your URL for seasonal or whatever purposes, the link will die because Tumblr isn't capable of forwarding to the new URL, but at least you won't make anyone unable to view their dash on mobile because trying to load your guide every time it's reblogged keeps crashing the app.
Bonus tip: Periodically check the reblogged links you've made in the past to make sure they're still active. A lot of times people change their URLs (sometimes only for a short period for seasonal changes), take down guides for whatever reason, or just take down their account which means the guide is no longer viable. You can update the URL for simple URL changes by clicking the "HTML" button and just swapping out the old blog name for the new one in the address (after "a href=" in the quotation marks). If the guide is just gone for whatever reason, then take down the link to it. If people are looking for information on something and they just keep finding dead links, it'll be more frustrating than helpful.