By doing a couple things you can not only maybe help yourself but do a huge favor to theme makers. By doing these couple of steps you can find out where the source of the problem is coming from:
01 Refresh & Test
The new customize appearance still has kinks in it that make the preview of it not always look right. Don’t rely on the preview. Make sure to refresh the customize page after installing it so that the customizable defaults for that theme show up and are rendered in the preview. Test blogs are always nice to check what your theme looks like live instead of the preview that is never correct.
02 Update Theme
If your theme still is off even on the test blog and not the preview in the customize page. Try and re-copy and paste the theme, maybe there was an update to the code you missed, maybe you accidentally didn’t copy all of the code. Re-install the theme just to make sure!
03 Check Appearance Options
Need to change a font, colors, font sizes? Make sure to check out the appearance section to see if the theme maker hasn’t already provided you options for that. If they haven’t for simple things like background color and un/bolding text W3schools explains well how to do simple CSS style changes.
04 Check FAQ & Answered Questions
Sometimes it can be daunting but often times you may be asking a question that has already been answered. Check the theme maker’s FAQ page or answered questions - who knows you might find what you’re looking for. If you don’t like wading through an ocean of text just CTRL + F search for some key words.
The internet is a vast space full of knowledge and answers. Basically magic when it comes to finding answers. Sure you have to sort through the duds but who knows, you might just find what you’re looking for.
Asking Theme Makers Questions:
If it comes to the point where you’ve tried and can’t solve the issue on your own, ask a theme maker but keep this acronym in mind.
Keep in mind that theme makers answer questions for free and by no means have to, so to avoid ask boxes getting closed just be mindful. You don’t have to say please and be formal and what not but a “Thanks!” at the end goes a long way.
Be specific! If it’s a certain theme make sure to mention it and explain as best you can. Questions is one thing but receiving vague questions isn’t much help to the theme maker or yourself. To help that, maybe read it over to make sure it would make sense to a stranger and that way you don’t have to play What, Where, and How? with theme makers.