Am I right to say that both Locke and Hume are empiricists? Their ideas are pretty similar but they seem to use human's experience as part as their argument differently but I can't seem to point out the specific differences.
I should say that some fairly significant differences separate Locke and Hume.
1 LOCKE : 'Experience : in that all our knowledge is founded'. But for Locke experience has a dual nature; it has two sources. 'Our observations employed either about external sensible things, or about the internal operations of our mind, perceived and reflected on by ourselves, is that which supplies our understanding with all the materials of thinking. These are the two fountains of knowledge from whence all the ideas we have, or naturally can have, do spring' (Essay, II.1.1). HUME, by contrast, does not divide the sources of experience in this way. Our experience has one source : perception or sensation, referred to as 'ideas'. From ideas derive impressions (memories of ideas - 'the faint images of impressions in thinking and reasoning' (Treatise, I.1.1). So experience is twofold for Locke, single for Hume.
2 In Hume, impressions cause ideas. In Locke, while sensation is necessary before the mind has anything to think about, reflection is an independent power that comes into play when the materials of sensation have been supplied. There is no direct causal relation between sensation and reflection in Locke as there is between impressions and ideas in Hume.
3 The notion of an 'idea' has a double reference in Locke, though he does not always appear to be aware of this. From one angle it is 'whatsoever is the object of the understanding when a man thinks' (Essay, 'Introduction', I.1.8). This is something like a propositional content. From another angle, an idea is a psychological event, an occurrence with antecedents and causes. The same double reference is present in Hume; possibly the propositional content aspect predominates in Hume but the matter is unclear.
4 Locke recognises persons as continuants; they are the subjects of experience. Experience can be attributed to them (Essay, II.27). For Hume it very much looks as if there are no continuants. Or to reduce the claim to safety : the continuing self is an illusion. Moreover, it is an illusion generated by experience. The succession of impressions and ideas creates the illusion that the succession is being experienced by a continuing subject (Treatise I.4.6). (Then to whom or what does the illusion occur ? Hume grapples unsuccessfully with the problem in the Appendix to the Treatise, and never returns to the topic again.)
5 Though Locke's position in the Essay is that we have no innate ideas since all ideas derive from experience, he does allow a non-empirical element into his moral epistemology. In his political writings, especially the Second Treatise of Civil Government, he assumes that by the use of reason we have access to the Natural Law which discloses the existence of natural rights. We can know by the use of reason that there are natural rights. Hume, on the contrary, offers a non-cognitive ethics. Reason can establish no moral truths. The origins of morality are to be traced to the 'passions', centrally the emotion of sympathy. (Hume, Treatise, III.1.1-2.)