First of all I would like to state that if 10% of google adwords marketing is facts and to do lists, 90% is optimizing and trying different strategies. So I am not gonna give you miraculous recipes for the best adwords account, instead you need to read through as much information as possible and find out what works for your account in order to create your own approach. One size never fits all but still;
1. Start speaking in your customers' language:
Empathize. If you were searching for outdoor apparel, what search terms would you use in google search bar? Thermal? Waterproof? Gore-tex? Maybe all. Consider all varieties. Some people look for table tennis ball, some look for ping pong ball and they mean same exact thing. Dive in for more and group them in different ad groups for high relevancy. If you have campaigns with one ad group and all keywords are stuffed together (believe me I have seen that A LOT); that means you are losing focus and money.
2. Consider 1 keyword ad groups:
While it is considered wise to build a keyword list with various terms for the same product, one keyword ad group is a good approach for exact generic/brand keywords in order to get high relevancy, high ad rank and possibly more conversions.
For example; if you have a campaign for shoes and ad group for sports shoes; group directly relevant keywords like "sports shoes" with different match types (Avoid using broad match only; exact and bmm preferably). And do this for each campaign. Also make sure using the term, for example "sports shoes", in the ad text for at least 3 times; in headline, body and display URL for improving relevancy.
3. Avoid using terms that are too generic:
You may want to attract traffic with general keywords like shoes, bags and shirts. All digital marketers love traffic. But what we love more is profit. So keep in mind that such keywords deplete the budget fast and are not as profitable as long tail keywords like men's training shoes, large shoulder bag and slim fit shirts. Moreover they will attract people who are probably just browsing. Instead; use two or three- word phrases that are more targeted.
Also avoid using Google's Opportunities tab for keyword stuffing without filtering since it sometimes suggests unrelevant and too general keywords that will hurt your return on ad spend.
4. Work on your negative keyword list as much as your positive list:
Negative keywords allow us to block unwanted or irrelevant search queries. For sure that does not mean you will aggresively add negative keywords and dry your account but instead by continuously analysing search reports; you may block the "misbehaving" keywords in order to reach your target audience. It also helps reducing cost, improve CTR, conversion rate, quality score and decrease cost/conversion. Sounds good, no? But use them wisely and be careful choosing the right negative keywords with right matches.
For example if you have the keyword "hd tv" and want to block search queries related to "tv shows" you should avoid adding that term as a broad keyword since it will prevent your ad showing for anything including the term "tv".
Negative keywords are also necessary when building a structure for cross-campaign approach. For example if you are targeting generic keywords like "tv", "ultra hd tv", "3d tv" in one campaign and brand keywords in another one like "samsung tv", panasonic tv", "sony ultra hd tv" etc. you need to make sure adding those keywords as negative in cross campaigns so that they do not outperform and compete with each other.
5. Do not put apples and pears in the same basket:
Google introduced "The Search With Display Select" that supposedly uses improved signals and methods for your ads to perform best. Fair enough. But Search and Display Networks belong to different worlds and has very different dynamics. So, better keep them separate untill something better comes up.
6. Use bid multipliers:
Have you ever heard of Silo/Mirror campaign strategy? Yes, that was a thing. It was basically when you break up your adwords account into parts targeting different networks, devices and locations (search vs display; mobile vs. desktop etc.) But today there is multipliers instead. If you like to boost your campaign on mobile more aggresively, you can adjust your mobile bid multiplier accordingly.
Bid multipliers are also very useful for targeting audience. For example if you have a remarketing campaign for X brand, you may choose to target different audiences like All Visitors, Engaged users, Buyers 30 days, Buyers 60 days, Members, Visitors of X brand etc. The return you will get from any user will be much more different than the one who shows interest in brand X by visiting its page so you better define a higher bid multiplier for that audience in order to boost its performance.
7. Test, test, test!
This is the most realistic and wise advice you will ever get from any adwords professional. I have tried all bid strategies, ad rotations, delivery methods, possible ad variations and audiences for the same exact campaign until I find the perfect combination of settings and content. That does not mean you approach to a point where no change is needed; adwords is introducing new concepts and updates almost every day and that means you need to adapt your account fast. Digital marketing is a world of "Be agile or die".
You are probably familiar with the concept of Split Testing already. In order to use that feature you need to have at least 2 ads per ad group. Adwords is not just about creating ads once and let the account alone forever. You need to come up with variations of ads with different titles, landing pages and propositions ( Such as using ads with price, discount rate or none).
Make sure to avoid overcomplicating and misleading ad while emphasizing your USP in each ad. You can even create mobile focused versions of your ads and set them to show on "mobile only". And one thing is very straightforward, pause whatever is not working for your business. Check KPIs like conversion rates, cost/conversion, return on ad sped and profit per impression on keyword level. Underperforming low quality keywords and ads will hurt your profitability in the long run so just focus on what is working best.