Part of my work as senior-consultant is to pick applicants and be part of recruitment and interviewing. I'd like to share a couple of easy things to mind when applying at tech-agencies. All of those I noticed throughout the years.

Context:
I'm a senior-consultant in a digital agency in Europe. The situation may and will differ for product-companies or start-ups. I have no experience with those. Most points are applicable everywhere, though.

When in doubt, overdress

Lots of people pay too little attention to their looks. One of the questions I ask myself about an applicant is: Could I send this person to our clients? Will they make a good impression? If you don't know the agency's dress-code, go for business-casual. No shorts. No worn-out or stone-washed clothes.

Don't rate your skills in ⭐️⭐️⭐️⭐️

I have seen lots of CVs with lists of technologies and skills, with an Amazon-style rating next to them. Don't do this. Nobody knows what it means, and you don't have room on the CV for a manual. When I read "JavaScript ★★★☆", does it mean that you're almost perfect? Or that you almost used it in production? A better way to communicate your skills is to list your main ones and add a short description of your experience in them.

Example:

JavaScript: Four years experience architecting JS-Apps and mentoring junior-developers

or

Erlang: Used in two personal projects

Show some presence on the web

If you apply for a web-related position, it's a plus if you have a website, a GitHub-Profile (if it's not dead) or a custom email-address (@johndoe .com instead of @gmail.com).
It's not vital, but it shows that you live in the medium. Make your CV available online, too.
I have seen personal-website-urls on CVs that lead to "under construction"-sites or were't available in some way. This is a huge red flag.

cv.contents.sortByRelevance()

Place the relevant items of your CV on top. With "relevant" I mean relevant for the position you're applying to. That means you might have to change it a bit for each company. If you apply to "3+ years experience developing for Android", and "Android" is one of the last items in your CV, or has only ★★☆☆, or I need to use the search-function to find it, it does not look good.

Negativity

Be careful with negativity in your communication. With that I mean: Talking sh** about former colleagues/bosses; criticising the company's website; questioning the validity of the recruiting-process; and so on.
Your points may be true and valid, but in a situation where your advancement depends on making the others feel good, you may want to reconsider bringing them up.

Gesture and Posture

Read up on behaviour that might be interpreted negatively in the cultural context you're applying in.
Mind your body-language. Sit up straight. Talk and ask. Don't interrupt others.
While waiting for the interviewers to pick you up in the lobby, don't sit down, so they won't have the "high ground" when they come get you. I learned this one in a seminar about talking and presenting, and I'm noticing it ever since.
Meeting the interviewers at eye level in all parts of the process is crucial to success.

Further reading

Those were just some little hints about things I noticed with applicants. There's an excellent long article by Patrick McKenzie about interviewing and careers in general. Read it next.