What about changing the balance of power outside of the European neighbor states, essentially tying England's hands and meaning the Royal Navy would be needed far, far away and comparatively hard-pressed vs. bottling up the German ports? An alliance with the USA after German unification could have happened, first and second generation Germans were a major share of the U.S. population, eventually outnumbering Americans with British Isles ties, and there are more commonalities with the freshly unified German states and the U.S. than the British empire (which we'd been at war with off and on for a century.) The industries and inputs are compatible while everyone was competing with British industries, technology, and science in the 19th century.
An enlightened Germany noticing that railroads cut into the overwhelming advantage of moving goods and commodities by water and applying that minor insight (clear from the American Civil War) focusing on becoming the railroad hub of Europe and building major multinational railroad companies to build and operate far past Germany's borders into Russia, the Balkans, Turkey, Spain, etc. is barely a POD. Oddly German investors funded much of America's railroad expansion so private capital was certainly available but doing it through companies rather than national railroads would also be less inflammatory...while the capital investment demands of Britain's colonies would make it a hard strategy to match. Rail networks of much greater capacity and reach across Eurasia would make a naval blockade vastly less threatening while also encouraging the Germans not to go too far in antagonizing it's trading partners all around it...probably considerably strengthen the Austro-Hungary Empire and Imperial Russian with better trade and access...transportation improvement always has a lot of unexpected ripples.
Using Krupp's artillery development prowess, taking port defense guns to a level of development seen in the WWI railroad guns, range far beyond line of sight and ship-killing shells would be a much lower cost way of making a blockade problemmatic, and shore batteries were still very popular then. Accelerating Zeppelin development slightly as a bombing platform against blockading ships in the 1880's-1890's before heavier-than-air aircraft are around would also avoid the shipbuilding waste and pressures perhaps.
Building and owning the transcontinental railroad systems of Eurasia with a technology race to build more efficient and reliable locomotives, safer and more enduring rolling stock, steel rail bridges, rail steel metallurgy, illuminated cars and tracks to allow operation past daylight, containerization/freight standardization, etc. all play to particular strengths of German industry and research then (and again is a very minor POD.)
You seem to be asking what types of POD best help Germany win a Naval war with the UK or at least a war with the UK. You can look at my signature for a TL. But to be more general, there are issues with the naval budget/strategy assuming you are not trying to increase the German military budget.
1) No strategy. The German Army had War Plans, as did the Russian Army, British Navy, French Army, etc. It is hard to win without a Plan.
2) Lack of fortified ports outside of Germany and China. Navies need bases to operate out of, or they lose much of their effectiveness. They don't need hugely expensive fortification like the German North Sea Coast or Portsmouth. A singel 30 cm gun, a few guns in the 20-29 cm range, a dozen or two dozen 15 cm guns, a few hundred mines, and a few coastal vessels would have made a world of difference. The British criticized Germany for only having a navy that could be used to attack the UK, and there is some truth to this. Having one fortified and improved port per colony would go a long way.
3) Lack of long range cruisers to protect merchant shipping. One warship in all of Indian Ocean and Atlantic. The German forces were too small for even a Naval war against France. Now to some extent, this could be fixed by moving some pre-dreadnoughts down, but they really are poorly suited for the role. Germany really could have used some long range (oil burning), 15-20cm, dreadnought gun configuration, 30 knot + ships, along with a few tankers. You probably could build at least 6 of these for the cost of a single dreadnought.
4) U-boats/torpedo boats at colonies. When I get into the details they were extremely useful and cheap.
5) Add a regiment of soldiers at each port. Since using native enlisted, NCO and company level officers, this is very cheap.
6) If you do 2-6 above, you know have a much more effect Navy with the same costs. Spee did more to help the war effort than the entire High Seas Fleet, all with older, less valuable ships. If you do this, you either get huge gains in the merchant war or more likely, the UK has to spread out its warships more. While this may seem more alarming to the modern person, it would have seem less alarming to the admirals of the RN because it is what they expected to happen. Also building one less capital ship every 2-4 years will lower tensions with the British and not really harm Germany in any way.
7) Germany would have hard time being an USA ally, but a better foreign policy would go a long way to keep the USA neutral, and some of the changes are easy, such as the Kaiser not making statements on international affairs that have not been edited by the diplomatic service. He often made statements that mad people made with no possible upside besides the Kaiser shooting his mouth off.
8) Germany had good rails, and the big one missing in WW1 was the Baghdad to Berlin railroad which was mainly a international pressure issue. What Germany really needed was to find a way to get Romania and Bulgaria to allow free movement of war materials in a war, but this is more a diplomatic move than a building more rail move.
9) The way to make the blockade less threatening would be to plan for one. Then there are lots of easy choice that help a lot. For example, becoming nitrogen independent through industrial nitrogen plants would have been easy to do. Have a food rationing plan that starts on day one of the war. Meat prices actually declined early in the war due to captured livestock. Something as simple as holding more of this stock overwinter in pastures in Belgium and France will help a lot. While Germany would still have had food issues in 1917 and 1918, the issues could be largely eliminated in 1915 and 1916, and much more moderate in 1917 and 1918. For example, A-H holding more of Galicia provides a much better food situation as would a plan where Poland was attacked first and the urban population was expelled. As would stockpiles of food, stockpiles of fertilizer, plans to convert fallow land to farm land quickly, etc.
10) More shore guns is a decent idea, especially in the colonies, but it does not break the blockade. And in defending ports, more mines would have been the most useful such as the mine system in Portsmouth. Very expensive, but a great system. One on the German coast would have freed up the surface ships to be more of a sword than shield.
11) Zeppelins were well used by the navy. A better use of airplanes was very possible, and likely someone like Prince Henry would have used them if he had not loss the political battle and become Inspector General or the equivalent Navy title.