hmmm.. i’d say that my biggest tip for how to deal with high school pressure is not to compare yourself to others. For as long as you live, whether in high school, college, professional school, work, forever and ever, there will always be someone who is more clever, or more beautiful, or more handsome than you! So the key is to be content with who you are, complete with your gifts and also your flaws.
Next, it is important to set realistic goals, with solid plans on how to achieve them. This will help you make progress, and might help reducing pressure/anxiety.