Being able to navigate around a website and easily find what you are looking for is perhaps the most critical aspect of website design.
It's no good having a super-whizzy looking site if visitors can't work out how they navigate the pages, but design and navigation shouldn't have to work against each other.
The main thing visitors look for is a menu at the top of the page - generally the 'Home' button is on the left and the 'Contact Us' link is on the right. Visitors tend to expect certain standard features, so don't veer too far away from these, even if you think you have something even better.
Anything on the website that can be clicked on should be obvious - personally I don't mind 'Click Here' text, as it's obvious, but choose other options to make the site more interactive such as text or images that change when the mouse cursor moves over them for example.
The way people use computers is pretty standard, for example scrolling down a website with the mouse wheel. Sometimes, designers use a scrolling image gallery on a page - great, they can be really effective, but if they are activated by the mouse scrolling, visitors will suddenly find the page they are scrolling down stops scrolling down and instead the image slideshow scrolls faster.
Landing pages...don't give visitors an extra click unless it is really necessary. Landing pages are a good way to put visitors off, and on top of this they are often really bad for your search engine performance as they usually contain nothing more than an image and the instruction 'Click to enter'!
The main menu should also stay consistent across all the pages of your website design. The actual menu options are fine to change, so long as you keep the 'Home' option in the same place all the time. Keeping the 'Contact Us' link on all pages is also a good idea to make sure your potential customers can always find this option wherever they are on your website.
Last but not least is making it obvious to visitors that the link they clicked actually did something! I've seen a website recently where all pages had the same image slideshow at the top - click a menu option and the new page loads below the slideshow on the page, so for modern widescreen monitors, it isn't obvious that anything has actually happened. I'll be honest, it even took me a short while to realise this was happening, I thought the menu was broken! As this was part of a website migration for a client, I hung around to work out what was happening, but potential clients may not be so patient!
Website menu's and navigation features should perhaps be the driving factor of any website design - from our perspective, we nearly always begin our website designs by creating the menu and navigation structure before we dive in to creating any content.
There should never be any need for visitors to need an explanation on navigating your website, if you feel they do then start again, it's too complicated!
Make sure that all of the ways visitors can use to move around your website are obvious and clear - letting someone else check any draft designs out is a great way to get an impartial view, as let's be honest, most of us website designers probably feel we got it right!