SEO and PPC are the main part of SEM. It has been found in the research that 70% of the users click on SEO results and remaining 30% click on PPC results. So concentrating on your your SEO efforts is always beneficial though SEO take time to deliver results than PPC. To handle these campaigns effectively, we need SEO Agencies or PPC Agencies like Radon Media(https://www.radon-media.com/) to make sure that you have selected the relevant keywords within your campaign budget and your SEM campaign delivers the desired results. Both of these are good examples of Pull Marketing Strategies.
If you want to boost your traffic get get leads in short time, PPC is best suited for your campaign.
Media buying is buying online traffic from website and promote your business products/services. Affiliate marketing is the process of paying a commission by promoting your products/services on other websites. These are the part of push marketing where we don't know that if the user is intended to buy you products/services. These campaigns are best suited for branding for your business.